Extend README following discussions

README.md

@@ -5,10 +5,14 @@ This collection of scripts allows you to easily set up a new OpenAppStack cluste
 As part of the bootstrap process a special control shell is installed (in the form of
 a Docker image) which contains utilities to manage your cluster.
 
-## Bootstrapping a new cluster
+## Prerequisites
+
+We assume a single-node setup for now.
 
 You need to have ssh access to the root account of the machine that will run
-your cluster. (We assume a single-node setup for now.)
+your cluster.
+
+## Bootstrapping a new cluster
 
 To run the bootstrap process:
 
@@ -21,8 +25,27 @@ stored in the cluster configuration and is used by the Traefik ingress
 controller, so even though using a domain name instead of an ip address may
 work at first, that is not recommended.)
 
+The bootstrap script will fire up your text editor to let you specify some
+basic configuration parameters that are needed to set up your cluster. When
+you're done editing, save and exit your editor, and the bootstrap process will
+continue.
+
 ## Managing an existing cluster
 
+The OpenAppStack project has created a special "control shell", a Docker
+container that you can run to perform administrative tasks on your cluster.
+Some programs that you can run from this shell:
+* `kubectl` is the Kubernetes control program. For example, run
+  `kubectl get pod` to see a list of pods that currently exist in your cluster.
+  Run `kubectl --help` for help.
+* `helm` is the "Kubernetes package manager". Use `helm ls` to see what apps are
+  installed in your cluster. You can also use it to perform manual upgrades;
+  see `helm --help`.
+* `helmfile` is a high-level tool to manage your app installations. For example,
+  run `helmfile -e oas diff` to view the differences between what's currently
+  installed and what should be installed according to the OpenAppStack
+  installation plan.
+
 To start the control shell, run
 
 ```