Have you tried looking at page 6 of the manual? (You can see it here if you don't have it handy.) What button?
These circular plastic pieces on the back actually are not buttons, they're screwed to the LCD frames and fit two holes of the back cover.Hi all,
someone could explain me what is the functionality of that button on the rear of tablet?
The Samsung cover has two small protruding nubs that lock into those indentations on the back of the 10.5. This keeps the cover firmly locked to the Tab S.