How do you lucid dream?

I saw something before online that said if you lay on your back and stay still, after a while you will get the urge to roll over. It said that's just your brain testing to see if you're awake. Then, your body will paralyze because your brain thinks you're asleep, and you will start to dream or halucinate. Well, is this how you do it? And how long would you normally need to do this until you finally start to lucid dream? And do you need to keep your eyes closed?