open up the grips. turn dipswitch 2 on (this unlocks it so you can program it). when the gun is off, hold trigger and turn gun on. you will see a bunch of colors (this is the programming mode). tap trigger until the light flickers red. (this is fire mode). hold trigger till light stops flashing. the light will then flash the number of times in which it is set. once it stops tap trigger once. light will flash and confirm. then turn off your marker. done.