(See diagram below)

MAGAZINE DISASSEMBLY:
Depress button protruding through hole in floorplate and slide floorplate off towards front of magazine.

MAGAZINE REASSEMBLY:
1) Insert follower as shown. High end of magazine spring should be towards rear of follower, contrary to what one might think should be the case. (Having the high end of the spring towards the rear gives a much needed boost to the last round out of the clip).

2) Compress spring to allow installing the floorplate. Slide the floorplate halfway into position - just enough to hold the spring compressed.

3) Install the spacer, sliding it between the back inside wall of the magazine and the back of the spring. Make sure the top of the spacer slides behind the follower and not under it.

4) Holding the bottom of the spacer to keep the spring compressed, slide the floorplate off to let the bottom of the spacer clear and then slide it all the way on, with the spacer held captive by the floorplate.

5) Depress the follower with the back of a pencil to ensure that the unit is assembled correctly.