To replace the motor housing, there’s 2 screws deep in the holes under the sticker on the base of the motor unit. I’ve keyed the replacement so it aligns like the original in the housing, you just need to make sure the screw holes & charge port all line up
As for the grinder insert, The original version screws into the grinder body so to get it out you need to pretty much destroy to old one. My replacement is a tight push fit & has a little key, which should align the two forks so they fit over the ribs that hold the upper bearing to make it a bit more secure
