I am new to programming and B4A. my place of work has sharepoint online and we have many sites (teamsites) in sharepoint. I would like to make app to connect to data in a sharepoint list of a site to show data on the app on mobile.
As a beginner you should start with simple projects. As Manfred writes you need to learn it. Nobody here will write you a complete solution as it isn't just 3 lines.