updated README.md

README.md

@@ -2,7 +2,22 @@
 JGame2D is a simple two-dimensional pixel art game for enhancing my java skills in fields of game development.<br>
 
 ## Installation
+### Pre-built package
 _To be continued_
 
+### Build from source (Linux)
+- **Step 1**<br>
+Clone the repository<br>
+```sh
+$ git clone https://git.miaurizius.de/MiauRizius/JGame2D.git
+```
+- **Step 2**<br>
+Run the build-script
+```shell
+$ ./build.sh
+```
+
 ## Contribution
-_To be continued_
+You currently cannot contribute to this project.<br>
+If you have any recommendations for improvements, 
+you can contact me via <a href="mailto:maurice@miaurizius.de">maurice@miaurizius.de</a>.