Followed step by step instructions (You could add to Reference RevitAPI.dll and RevitAPIUI.dll)
I Get 930 Errors: CS0115 --no suitable method found to override for BuiltinParameter.Groups, Category.ComponentGuid…etc. when tried to build. Thank you!
If you update your Visual Studio to version 15.9 it should work fine without adding any additional Reference.
It did! Thank you Kike.