Facing a lot of problems yet you only mention 1 problem.
Have you tried to debug the app or did you just build it ? It looks like all you’ve done is added one line of XML and 1 CL line.
Usually debugging will show you the problem that is giving the white screen.
https://taco.visualstudio.com/en-us/docs/debug-using-visual-studio/
This is similar to using Google Chrome inspector on your android phone.