Ok - in this forum, the rules are that you try something on your own first and then when you hit a snag, we will try and help. If you do not do this you will end up not learning, but always relying on others to achieve your goals.
This time I am going to break the rules to get you started.
Firstly, on the right of your IDE, you need to select the Libraries Manager (at the bottom) and then look for the "Phone" Library. Once you have done this the "Phone" library becomes available for use.
Now in your Sub Globals you need to add this
Dim pws As PhoneWakeState
Then, in Sub Activity_Create....., add this
Sub Activity_Create(FirstTime As Boolean)
pws.KeepAlive(True) ' Will keep the phone in wake state with a bright screen
End Sub
My next recommendation - work through these - they will bring you to speed very, very quickly
https://www.b4x.com/android/forum/threads/b4x-erel-teaches-programming-video-tutorials.88787/
Enjoy !!