I think I tried to explain this once before...as these plastics have to be removed to access the front brake fluid reservoir, too....you must remove the 4 visible screws and the 2 'bolts' down low, 1 on each side. I can't recall if you must also loosen the front plastic cover, too...it might be necessary.
The trick to removing the rear cover is to pull out on each lower side before you pull it back. You have to clear the bolt holes..
Just looked at scoot..yes, front cover must come off before rear or along with rear, remove windshield and then start unscrewing and gently pulling and tugging...not very intuitive but can be done. Good luck!