Place your reference image on the lightbox. Then, place your blank paper on top of it. This is called “the tracing sandwich,” and it’s the most exciting thing you’ll do all week (don’t @ me).
Use a tiny bit of tape at the corners to hold everything in place. If you skip the tape, the paper will slide the second you breathe, and you’ll draw a cat with a nose that migrated to its ear. Trust me, I have a shoebox full of those mistakes.