Add 608 Bearing to the upperside of the handle (press fit)

Ad 608 Bearing to the inside of the handle (press fit)

Add M8 threaded rod to the drum. If it's too tight by hand use your powerdrill to thread it in. The rod should be 90mm + drum height in total length. If it's too loose or get loose during work, secure it with a little bit of superglue.

Put the drumassembly into the handle. Make sure the side with the small circular extend faces the bearing.

Add the M8 nut and tighten it. Now you can also put on the cap for the handle

Add the sandpaper

Lock the sandpaper into place by rotating the locking mechanism about 90° with an 6mm allen key. When the locking mechanism is not loose in the first place, by rotating it with the allen key it should get loose.