Remove forks, clean & dry thoroughly using a contact cleaner or a small amount of washing liquid. For best results, make sure forks are smooth without any stone chips, etc.
After checking you have the correct sleeve on the correct fork leg, slide into position and check the bleed screw on the top of the leg so that it faces forwards and ensure the sleeve logo faces outwards. Make sure the sleeve slides down over both of the forkseal ridges.
With the heat gun set to a medium to high heat, starting on the creased area of the sleeve, gently heat up & down the entire sleeve while constantly turning the fork leg. Make sure you don't keep the heat on one area for too long.
Make sure there aren't any bubbles or imperfections before installing the forks back on the bike. If you have any small bubbles just apply direct heat to the area for no more than 2 seconds.
Please refer to your owners manual and reinstall the forks back on your bike.