Address user feedback, closes #328

docs/installation_instructions.md

@@ -26,13 +26,13 @@ guide][https://openappstack.net/contact.html).
 ## Prerequisites
 
 * A virtual machine or bare metal server with:
-  * current Debian stable "buster";
-  * a public IP address;
+  * Current Debian stable "buster";
+  * A public IP address;
   * 6GB of RAM;
-  * at least 20GB of disk space for installation, plus more for application
+  * At least 20GB of disk space for installation, plus more for application
     data;
   * root ssh access.
-  * python installed
+  * Python installed
 * A trusted local machine to run the installer on:
   * You need Python 3 and Git installed (`apt install python3 git`)
   * We recommend using a [python virtualenv](https://docs.python.org/3/tutorial/venv.html)
@@ -198,9 +198,14 @@ propagate.
 You need one dedicated (sub)domain entry and a wildcard entry for everything
 inside it. For example, create an A record for these domains:
 
-- An `A` record `oas.example.org` pointing to the VPSs IP address
+- An `A` record `oas.example.org` pointing to the VPSs IP address,
 - A `CNAME` record `*.oas.example.org` pointing to `oas.example.org`.
 
+> **NOTE:** It is also possible to host openappstack on a domain (with no
+> dedicated subdomain). In that case, make these DNS records instead:
+> - An `A` record `example.org` pointing to the VPSs IP address,
+> - A `CNAME` record `*.example.org` pointing to `example.org`.
+
 OpenAppStack will fetch https certificates with [Let's
 Encrypt](https://letsencrypt.org) by default. In order to do this DNS entries
 need to be created.  If you don't need https certificates for your cluster while