Hi Kikloo,
I do understand you very well, as when I started using B4A I was also having problems understanding screen layouts.
Please do not quit. Actualy it is not very complicated, but as everything in life there is a learning curve. Read the tutorials, specialy dedicate sometime understanding the designer scripts, as they are a key element for success with diferent layouts.
When planning your app, plan carefully the screen layout and the user interface so that it becomes easier to manage whatever screen size the app is running in.
I still consider myself as a begginer, and everyday I learn by digging in this forum and reading , examining and playing with examples. I can assure you that currently you won't find better option than Basic 4 Android.
I managed to do a complete application for my company runing in several screen sizes. Once I understood how this android OS operates, suddenly everything started to make sense and productivity jumped to very high levels.
Practise, practise, practise
and place your doubts in the forum. This forum does work.