After some tests on WebOS 23 on the home screen, you can just remove the ads, remove all the tiles (or cards) except the "Mofify" card that will stay in the middle of the screen. Concerning the "Apps" bar, you cannot remove some specific ones like the browser, the dashboard, ... And finaly the bottom items cannot be removed at all (you can just remove the recommendations from the general parameter menu). To summarize, you cannot customize the home screen ... It is really a pity.