Select(control)
Select(control, row or column)
Select(control, row or column, child control)
Select(Index(gallerycontrol.AllItems, row or column).child control)
This is the same functionality as the Power Apps Select function.
When working with a nested gallery, use Index() within the select function.
Select(Button1)
Select(Gallery1,1)
Select(Gallery1,1,Button1)
Select(Index(Gallery1.AllItems, 2).Icon2)
Select(Index(Index(Gallery1.AllItems, 1).Gallery2.AllItems, 4).Icon3);