New to ignition perspective Mobile Interface

I just start to learn the perspective module working on mobile phone, this is very new for me, upside is my mobile phone app version.
question 1: My iphone is 12Pro, when I open the app, there are still some pace is black and empty, how to use the upside and downside space?

Question 2: I know how to add the project to the mobile phone , but don’t know how to delete it
Many thanks in advance.