docs: update README formatting and some additional info

Signed-off-by: Riyaz Faizullabhoy <riyaz.faizullabhoy@docker.com>

README.md

@@ -1,14 +1,32 @@
+# Moby
+
 Moby, a toolkit for custom Linux distributions
 
+## Getting Started
+
+### Build
+
 Simple build instructions: use `make` to build.
+This will build the Moby customisation tool and a Moby initrd image.
 
-`make qemu` will boot up a sample in qemu in a container; on OSX `make hyperkit` will
-boot up in hyperkit. `make test` or `make hyperkit-test` will run the test suite.
+#### Requirements:
 
-Requires GNU `make`, GNU or BSD `tar` (not Busybox tar) and Docker to build.
+- GNU `make`
+- GNU or BSD `tar` (not Busybox tar)
+- Docker
 
-To customise, copy or modify the `moby.yaml` and then run `./bin/moby file.yaml` to
-generate. You can run the output with `./scripts/qemu.sh` or `./scripts/hyperkit.sh`.
+### Booting and Testing
+
+- `make qemu` will boot up a sample Moby in qemu in a container
+- on OSX: `make hyperkit` will boot up Moby in hyperkit, and also download hyperkit and vpnkit binaries for later use
+- `make test` or `make hyperkit-test` will run the test suite
+
+## Customise
+
+To customise, copy or modify the [`moby.yaml`](moby.yaml) to your own `file.yaml` and then run `./bin/moby file.yaml` to
+generate its specified output. You can run the output with `./scripts/qemu.sh` or `./scripts/hyperkit.sh`.
+
+### Yaml Specification
 
 The Yaml format is loosely based on Docker Compose:
 
@@ -20,6 +38,6 @@ The Yaml format is loosely based on Docker Compose:
 - `outputs` are descriptions of what to build, such as ISOs.
 
 For the images, you can specify the configuration much like Compose, with some changes, eg `capabilities` must be specified in full, rather than `add` and `drop`, and
-there are no voluems only `binds`.
+there are no volumes only `binds`.
 
 The config is liable to be changed, eg there are missing features (specification of kernel command line, more options etc).