Optional Step 1:

Grab the scroll wheel

Optional Step 2:

Take the rubber off of its resting place

Optional Step 3:

Attach the TPU scroller wheel to the scroller at an angle for easier application

Optional Step 4:

It should look like this →

Step 1:

Grab your base and slide your positive lead (soldered connection facing downwards) on the front end.

Step 2:

Do the same to the negative lead, this time with the soldered connection facing up

Step 3:

Place the Optical Lens and the Toggle switch in their respective slots. Make sure the Optical Lens is facing the right way (circle pointing towards the positive lead). Make sure to slide the toggle switch all the way to the middle of the base.

Step 4:

Making sure that the on-switch and the toggle switch are lined up, gently place the mainboard (with scroll wheel attached) onto the base.

Step 5:

Place the fastener on top of the mainboard

Step 6:

Attach the fastener to the the base with a screw from the kit like so →

Step 7:

Place your AA battery in its designated slot

Step 8:

Slide the negative lead into the back pocket

Step 9:

Attach the cover of your choice and screw the base and the cover together. Attach the anti-friction pads to the bottom in their respective slots. The USB receiver can be friction fit in the hole at the bottom. After some testing, it will not fall out unless pulled.

Simplified Exploded View: