Congratulations on finding yours for $15, I paid $25 for mine and I was glad to get it. I use mine for transferring Red work patterns onto fabric. You put the paper pattern (as Alexandra said) on the light box, lay your fabric square on top of the paper and use a fabric pen/pencil to mark the lines. I use my Frixion pen for Red Work since I will be embroidering over it. If you were going to do something else you might want to use a water solvable pen/pencil that you could remove.