Steps to modify and rebuild Android App

With the helpful community and the documentation provided, I could able to run the server with the client in my local machine along with cosmetic changes required in my server.

I am trying to rebuild Android app so that I could accommodate few cosmetic changes but couldn’t do it.

I am trying to do following changes and rebuild the app:
a) to be able to connect through my server only
b) to be able to customize the name of the app with mobile app logo (rebranding etc)
c) and rebuild

Being a newbie,i even followed this documentation but couldn’t, therefore looking for any help or point me to similar thread please?

Thanking you in advance.