Modding Tutorials/Decompiling source code

The base game provides a bunch of code snippets in ../Source/, relative to your Rimworld installation.
Since this isn't a lot, one might want to take a look at the game's full source code;

1. Download ILSpy (Download Binaries) and extract it to a directory of your choosing. Optionally create a desktop shortcut;
2. Either: associate the .dll extension with ILSpy (go to 3.) or open ILSpy and open a .dll (go to 6.);
3. Navigate to Assembly-CSharp.dll in ../Rimworld***_Data/Managed/, relative to your Rimworld installation and with *** being a version number;
4. Right-click "Open with" and select a standard program. Navigate to your ILSpy installation and double-click ILSpy.exe, tick the checkbox and accept;
5. Double-click Assembly-CSharp.dll (go to 9.);
6. Open ILSpy;
7. Go to File -> Open or press Ctrl+O, navigate to ../Rimworld***_Data/Managed/, relative to your Rimworld installation and with *** being a version number;
8. Select Assembly-CSharp.dll and confirm;
9. Click the "+" next to Assembly-CSharp (***), you will now see a list including the items Rimworld and Verse;
10. Take your time to look through the source code, to make yourself familiar. If you ever need the source code, open ILSpy again.