WIP on-boarding

CONTRIBUTING.md

@@ -16,4 +16,37 @@ If you encounter a problem or have an idea about how to make PixelDroid better,
 
 You can also help us solve one of the existing issues, or improve the application in some other way, by contributing changes yourself. To do this you can fork the project and submit a Merge Request.
 
-Before starting to work on an issue or an improvement, you can ask us on our Matrix channel (#pixeldroid:gnugen.ch) what we think, or make a comment on the relevant issue, so that we might point you in the right direction, and to make sure someone else is not already working on it.
+Before starting to work on an issue or an improvement, you can ask us on our Matrix channel (#pixeldroid:gnugen.ch) what we think, or make a comment on the relevant issue, so that we might point you in the right direction, and to make sure someone else is not already working on it.
+
+## How to get started
+
+Download the latest version of [Android Studio](https://developer.android.com/studio)
+
+TODO: explain cloning git submodules
+
+When first opening the project, you might encounter this issue: 
+
+![Gradle issue](Screenshots/gradle-issue.png)
+
+F-Droid requires ``distributionSha256Sum``. You are given three links to solve this issue, choose the first one:
+
+![Click on this link](Screenshots/gradle-solution.png)
+
+### Changing Gradle dependencies
+
+Every time you change any dependency in ``build.gradle``, you will encounter the following error:
+
+![Gradle dependency](Screenshots/gradle-dependency-verification.png)
+
+TODO: explain why
+
+In the top toolbar, go to ``Edit Configurations... > Gradle `` and click on ``+`` in the top left corner to add a new run configuration. In the field ``Run``, write the command that triggered the dependency error, which in your case is probably ``assembleDebug`` (command executed when pressing the play button) and give it the arguments ``--write-verification-metadata sha256``.
+
+![Run Configuration](Screenshots/run-configuration.png)
+
+You can now run PixelDroid with your new configuration
+
+![Run with new config](Screenshots/run-new-config.png)
+
+This has to be done only once when you encounter this error, then you can run the app as usual again.
+TODO: explain what it did