To remove the switch boot, you should be able to pinch it between your thumb and forefinger and just pull it out the back of the pack. The retaining o-ring may or may not come out with the boot. If not, you will want to remove it as well. with a small diameter pic or needle you can fish the retaining O-ring out. All that's left is the switch and if you wish to remove it, it will unscrew out the back using some needle nose or round nose pliers ot cir-clip pliers or similar tool used in the two drive holes on the top of the switch body. With the switch firmly tightened in the pak, you would then install the boot and insure that its flange is seated evenly down in the groove in the pak. You then insert the retaining O-ring into this groove on top of the flange working it securely into the groove as you work around the circumference. Hope that helps.