doc: fix cumulative issues in GSG from DX study

Address a collection of small issues in the GSG:
- remove mention of the (optional) serial port use
- update recommended development computer memory size
- mention why there are six user VM launch scripts (and that we're only going to
  use one of them)
- clarify how OS installed for running board inspector is modified with
  the Linux kernel built using board and configuration information
- add commands used to confirm files are in the expected directories
- remove specific BIOS example (keep just settings info)

Signed-off-by: David B. Kinder <david.b.kinder@intel.com>

doc/getting-started/getting-started.rst

@@ -34,7 +34,7 @@ Before you begin, make sure your machines have the following prerequisites:
 
 * Hardware specifications
 
-  - A PC with Internet access (A fast system with multiple cores and 16MB
+  - A PC with Internet access (A fast system with multiple cores and 16GB
     memory or more will make the builds go faster.)
 
 * Software specifications
@@ -55,7 +55,6 @@ Before you begin, make sure your machines have the following prerequisites:
   - USB keyboard and mouse
   - Monitor
   - Ethernet cable and Internet access
-  - Serial-to-USB cable to view the ACRN and VM console (optional)
   - A second USB disk with minimum 1GB capacity to copy files between the
     development computer and target system
   - Local storage device (NVMe or SATA drive, for example)
@@ -72,10 +71,6 @@ To set up the hardware environment:
 
 #. Connect the target system to the LAN with the Ethernet cable.
 
-#. (Optional) Connect the serial cable between the target and development
-   computer to view the ACRN and VM console (for an example, see
-   :ref:`connect_serial_port`).
-
 Example of a target system with cables connected:
 
 .. image:: ./images/gsg_nuc.png
@@ -215,7 +210,7 @@ To install Ubuntu 18.04:
 
    .. image:: ./images/gsg_ubuntu_install_01.png
 
-#. Use the checkboxes to choose whether you'd like to install Ubuntu alongside
+#. Use the check boxes to choose whether you'd like to install Ubuntu alongside
    another operating system, or delete your existing operating system and
    replace it with Ubuntu:
 
@@ -242,20 +237,10 @@ Configure Target BIOS Settings
      assist for CPU virtualization).
    * Enable **VT-d** (Intel Virtualization Technology for Directed I/O, which
      provides additional support for managing I/O virtualization).
-   * Disable **Secure Boot**. This simplifies the steps for this example.
+   * Disable **Secure Boot**. This setting simplifies the steps for this example.
 
    The names and locations of the BIOS settings differ depending on the target
-   hardware and BIOS version. You can search for the items in the BIOS
+   hardware and BIOS version.
-   configuration editor.
-
-   For example, on a Tiger Lake NUC, quickly press :kbd:`F2` while the system
-   is booting. (If the GRUB menu or Ubuntu login screen
-   appears, press :kbd:`CTRL` + :kbd:`ALT` + :kbd:`DEL` to reboot again and
-   press :kbd:`F2` sooner.) The settings are in the following paths:
-
-   * **System Agent (SA) Configuration** > **VT-d** > **Enabled**
-   * **CPU Configuration** > **VMX** > **Enabled**
-   * **Boot** > **Secure Boot** > **Secure Boot** > **Disabled**
 
 #. Set other BIOS settings, such as Hyper-Threading, depending on the needs
    of your application.
@@ -323,7 +308,7 @@ Generate a Board Configuration File
 
          ls /media/$USER
 
-      Confirm that one disk name appears. You'll use that disk name in
+      Confirm that only one disk name appears. You'll use that disk name in
       the following steps.
 
    #. Copy the board inspector tool folder from the acrn-hypervisor source code to the USB disk:
@@ -361,7 +346,9 @@ Generate a Board Configuration File
       sudo python3 board_inspector.py my_board
 
 #. Confirm that the board configuration file ``my_board.xml`` was generated
-   in the current directory.
+   in the current directory::
+
+      ls ./my_board.xml
 
 #. Copy ``my_board.xml`` from the target to the development computer
    via USB disk as follows:
@@ -390,7 +377,7 @@ Generate a Board Configuration File
 
 .. rst-class:: numbered-step
 
-Generate a Scenario Configuration File and Launch Script
+Generate a Scenario Configuration File and Launch Scripts
 *********************************************************
 
 You use the **ACRN configurator** to generate scenario configuration files and
@@ -400,9 +387,10 @@ A **scenario configuration file** is an XML file that holds the parameters of
 a specific ACRN configuration, such as the number of VMs that can be run,
 their attributes, and the resources they have access to.
 
-A **launch script** is a shell script that is used to create a User VM.
+A **launch script** is a shell script that is used to configure and create a
+User VM. Each User VM has its own launch script.
 
-To generate a scenario configuration file and launch script:
+To generate a scenario configuration file and launch scripts:
 
 #. On the development computer, install ACRN configurator dependencies:
 
@@ -438,7 +426,7 @@ To generate a scenario configuration file and launch script:
          :class: drop-shadow
 
    #. In the dialog box, select **shared** as the default scenario setting and
-      then click **OK**.
+      then click **OK**. This sample default scenario defines six User VMs.
 
       .. image:: ./images/gsg_config_scenario_load.png
          :class: drop-shadow
@@ -455,16 +443,17 @@ To generate a scenario configuration file and launch script:
 
    #. In the dialog box, keep the default name as is. Type
       ``/home/<username>/acrn-work`` in the Scenario XML Path field. In the
-      following example, acrn is the username. Click **Submit** to save the
+      following example, ``acrn`` is the username. Click **Submit** to save the
       file.
 
       .. image:: ./images/gsg_config_scenario_save.png
          :class: drop-shadow
 
-   #. Confirm that ``shared.xml`` appears in the directory
+   #. Confirm that ``shared.xml`` appears in your ``acrn-work`` directory::
-      ``/home/<username>/acrn-work``.
 
-#. Generate the launch script:
+         ls ~/acrn-work/shared.xml
+
+#. Generate the launch scripts:
 
    a. Click the **Launch Setting** menu on the top banner of the UI and select
       **Load a default launch script**.
@@ -473,7 +462,8 @@ To generate a scenario configuration file and launch script:
          :class: drop-shadow
 
    #. In the dialog box, select **shared_launch_6uos** as the default launch
-      setting and click **OK**.
+      setting and click **OK**. Because our sample ``shared`` scenario defines six
+      User VMs, we're using this ``shared_launch_6uos`` launch XML configuration.
 
       .. image:: ./images/gsg_config_launch_load.png
          :class: drop-shadow
@@ -490,8 +480,9 @@ To generate a scenario configuration file and launch script:
       .. image:: ./images/gsg_config_launch_save.png
          :class: drop-shadow
 
-   #. Confirm that ``launch_uos_id3.sh`` appears in the directory
+   #. Confirm that ``launch_uos_id3.sh`` appears in the expected output directory::
-      ``/home/<username>/acrn-work/my_board/output/``.
+
+         ls ~/acrn-work/my_board/output/launch_uos_id3.sh
 
 #. Close the browser and press :kbd:`CTRL` + :kbd:`C` to terminate the
    ``acrn_configurator.py`` program running in the terminal window.
@@ -523,7 +514,7 @@ Build ACRN
       make -j $(nproc) targz-pkg
 
    The kernel build can take 15 minutes or less on a fast computer, but could
-   take 1-3 hours depending on the performance of your development computer.
+   take an hour or more depending on the performance of your development computer.
 
 #. Copy all the necessary files generated on the development computer to the
    target system by USB disk as follows:
@@ -540,6 +531,9 @@ Build ACRN
          cp ~/acrn-work/acrn-hypervisor/build/acrn-2.6-unstable.tar.gz $disk/
          sync && sudo umount $disk/
 
+      Even though our sample default scenario defines six User VMs, we're only
+      going to launch one of them, so we'll only need the one launch script.
+
    #. Insert the USB disk you just used into the target system and run these
       commands to copy the tar files locally:
 
@@ -556,6 +550,10 @@ Build ACRN
          cd ~/acrn-work
          sudo tar -zxvf linux-5.10.52-acrn-sos-x86.tar.gz -C / --keep-directory-symlink
 
+      This tar extraction replaces parts of the Ubuntu installation we installed
+      and used for running the board inspector, with the Linux kernel we built
+      based on the board and scenario configuration.
+
    #. Extract the ACRN tools and images:
 
       .. code-block:: bash
@@ -579,7 +577,7 @@ Install ACRN
 
 In the following steps, you will configure GRUB on the target system.
 
-#. On the target, find the root file system (rootfs) device name by using the
+#. On the target, find the root filesystem (rootfs) device name by using the
    ``lsblk`` command:
 
    .. code-block:: console
@@ -719,9 +717,7 @@ In the following steps, you will configure GRUB on the target system.
 Run ACRN and the Service VM
 ******************************
 
-When the ACRN hypervisor starts to boot, the ACRN console log will be displayed
+The ACRN hypervisor boots the Ubuntu Service VM automatically.
-to the serial port (optional). The ACRN hypervisor boots the Ubuntu Service VM
-automatically.
 
 #. On the target, log in to the Service VM. (It will look like a normal Ubuntu
    session.)
@@ -755,7 +751,9 @@ Launch the User VM
 
    #. Put the ISO file in the path ``~/acrn-work/`` on the target system.
 
-#. Open the launch script in a text editor. The following command uses vi, but
+#. Even though our sample default scenario defines six User VMs, we're only
+   going to launch one of them.
+   Open the launch script in a text editor. The following command uses ``vi``, but
    you can use any text editor.
 
    .. code-block:: bash
@@ -791,8 +789,9 @@ Launch the User VM
       sudo chmod +x /usr/sbin/iasl
       sudo ~/acrn-work/launch_uos_id3.sh
 
-#. Confirm that you see the console of the User VM on the Service VM's terminal
+#. It will take a few seconds for the User VM to boot and start running the
-   (on the monitor connected to the target system). Example:
+   Ubuntu image.  Confirm that you see the console of the User VM on the Service
+   VM's terminal (on the monitor connected to the target system). Example:
 
    .. code-block:: console