feat: link and mention demo repo

Author: pmbittner

README.md

@@ -72,7 +72,12 @@ In case you are using Nix Flakes, you can skip cloning the repository as usual:
 Afterward, the [result](result) symlink points to the [Javadoc](result/share/github-pages/DiffDetective/docs/javadoc/index.html), the [DiffDetective jar](result/share/java/DiffDetective/DiffDetective.jar) and a simple [script](result/bin/DiffDetective) for executing a DiffDetective main class provided as argument (e.g., evaluations used in previous research, see below under 'Publications').
 
 
-## Usage Demonstration
+## How to Get Started
+
+For a demonstration on how to get started using the library, we have prepared a demo repository [here](https://github.com/VariantSync/DiffDetective-Demo).
+You may clone it as a template and example for including the library into your own projects.
+Additionally, there is a screencast available on YouTube, guiding you through the demo's setup and source code:
+
 [![DiffDetective Demonstration](docs/yt_thumbnail.png)](https://www.youtube.com/watch?v=q6ight5EDQY)