1. Turn off the Apple watch, put the rubber sleeve on the movement and align
the rubber sleeve holes
2. Use a screwdriver to unscrew the 4 screws on the back cover of the case and
place it in a safe area to avoid loss.
3. Put the apple watch with the silicon cover installed into the case
and align the knob of the movement with the knob of the case.
4. Install the back cover of the case
(the gap of the back cover needs to be aligned with the gap of the case)
5. Install the back cover screws
(first put all 4 into one-third, and then cross-tighten them one by one)