Add Prerequisites and Getting help to Contributing.md (#6682)

CONTRIBUTING.md

@@ -12,6 +12,21 @@ Pull requests are welcome!
 If you're interested in taking on [an open issue](https://github.com/tachiyomiorg/tachiyomi/issues), please comment on it so others are aware.
 You do not need to ask for permission nor an assignment.
 
+## Prerequisites
+
+Before you start, please note that the ability to use following technologies is **required** and that existing contributors will not actively teach them to you.
+
+- Basic [Android development](https://developer.android.com/)
+- [Kotlin](https://kotlinlang.org/)
+
+### Tools
+
+- [Android Studio](https://developer.android.com/studio)
+- Emulator or phone with developer options enabled to test changes.
+
+## Getting help
+
+- Join [the Discord server](https://discord.gg/tachiyomi) for online help and to ask questions while developing.
 
 # Translations