do not write "this document describes" twice

docs/installation_instructions.md

@@ -5,9 +5,9 @@ installation process wil set up a "Kubernetes cluster" which runs several open
 source applications. More information about the applications can be found on the
 [OpenAppStack website](https://openappstack.net/).
 
-This document describes how you can set up a "single-node" OpenAppStack cluster.
-This means everything runs on the same VPS.  Support for "multi-node" clusters
-(a Kubernetes cluster on more than one VPS) will come in the future.
+We will set up a "single-node" OpenAppStack cluster.  This means everything runs
+on the same VPS.  Support for "multi-node" clusters (a Kubernetes cluster on
+more than one VPS) will come in the future.
 
 > **NOTE:** All commands in these installation instructions need to be run on a
 > trusted provisioning machine (i.e., your laptop) that is *not* the VPS that