What you haven't seen are the other 27 pictures which didn't come out as well. But the technique is easy. I started by reading this digital-photography-school.com/beginners-guide-to-light-painting/ and this digital-photography-school.com/how-to-shoot-light-trails/
Setting up the camera took some time. The best tip I can give is turn off long exposure NR. It means everything takes twice as long.
You need a dark room because you are going to be using speeds measured in seconds (like 20). For the circles, remember to keep moving - that way, the body holding the light won't appear. The ghost was easy - I just asked the piano player to leave after 10 seconds of a 20 second shot. My camera has a countdown timer built in, so it was easy to know when 10 seconds was up.
It is great fun to do - and you can do it in your living room.
Alan