INSTALL: extended Nix instructions

Author: pmbittner

INSTALL.md

@@ -117,18 +117,26 @@ See [REQUIREMENTS.md](REQUIREMENTS.md) for instructions on how to install Nix an
 > Otherwise, the Nix setup might fail due to incompatibilities with the file system.
 > Moreover, if you would like to have access to the demo's GUI, you need an XServer installed (see [REQUIREMENTS.md](REQUIREMENTS.md)).
 
-Clone and navigate to this repository.
-Then simply build and run the Demo using
+> Notice for Nix flake users:
+> If you have flakes enabled, you can just use `nix run github:VariantSync/DiffDetective-Demo` to run the demo instead of the following instructions.
+
+Clone and navigate to this repository in a terminal.
+Then simply build the Demo with
 ```shell
 nix-build
-./result/bin/DiffDetective-Demo
 ```
 
-If you have flakes enabled, you can instead just use
+Afterwards, the produced jar file is located at `result/share/java/DiffDetective-Demo.jar`.
+You can run it manually with Java (requires Java 17 or higher):
+```shell
+java -jar result/share/java/DiffDetective-Demo.jar
+```
+or alternatively via nix:
 ```shell
-nix run github:VariantSync/DiffDetective-Demo
+./result/bin/DiffDetective-Demo
 ```
 
+
 ## Expected Output
 
 The expected output is close to the output shown at the end of the [screencast](https://www.youtube.com/watch?v=q6ight5EDQY).