Find a relatively flat, non-rubberized surface. The adhesive will not stick well to rubberized surfaces. Without removing the adhesive backing, place the base clasp on the intended spot and ensure that the microphone is going to be pointed towards your mouth. Rotate the base clasp if needed. Wipe the surface clean with the included alcohol pad, remove the backing from the base clasp, and hold firmly for 30 seconds. For best results, let it cure for 1 hour before attaching your ModMic.
For difficult or mesh surfaces you can try warming the adhesive with a hair dryer or similar low heat source. Be sure not to burn the adhesive, yourself, or your headphones.