The white cover is held in place by a few triangular head screws in some Roomba 880’s. They do however screw in very lightly, so you might be able to remove them using a 2,2-2,4 mm flat screwdriver.
Start removing the black face plate from the front of the robot - on the back (where the dust container button is) it is held by two “hooks” , which you need to slide backwards rather than pry upwards.
Some Roomba 880 models (either newer or older than the one above) have more black screws holding this black panel in place. You need to remove all 14 of them. 4 screws are hidden under the handle, so you need to remove it first in order to reach them - this can be done by pushing the handle backwards while folded - it should clip out of its hinges.