The "android home screen indication at the bottom of the screen" is either the navigation bar (the three-button system for back, home, and recents) or the gesture bar (a thin line used for gesture navigation
The current phone are allowed only 3 application you can added into navigation bar
Open the application that you want to keep, go to navigation bar
Locate icon on top on application then double tap
Select keep open
It will lock the application into your location
Do the same as second and third
When never you closed navigation bar. Those 3 still be there
To unlock, look for padlock on each application. It will unlocked
