How can I set the home screen button to set to the screen that I want to use as my home screen?
To set the home screen, go to any of the screens and with two fingers (thumb and forefinger) , pinch the screen.
That will then display all front screens and also allow you to add or delete screens.
From there you will see each existing screen has a little 'home' icon in the top right. Just click the 'home' icon of whichever screen you want to be home.
I hope that makes sense.