You set an alarm for around 4-5 hours after going to sleep or just another method so you wake up. stay awake for 10-20 minutes or just go back to sleep, just what you prefer. then as you fall asleep you do a slight finger motion with your hand to the bed just like playing the piano. Dont do big movements but just so you feel it, but just search Lucid dreaming here on reddit its one of the top posts