The tiles on the home screen change as you do things. In general, as you open books, the browser, games etc. they appear on the home screen and push the others of. You can remove most tiles with a long press and choosing "Dismiss" from the menu. If you are a calibre user, my Kobo Utilities plugin has a function to dismiss some of the tiles and prevent them from coming back.
And I outline the basic UI standards in
https://www.mobileread.com/forums/sho....php?p=2772640.