To trace the pattern, secure the black paper face up with some masking tape. Rub white chalk on the back of your pattern, then tape the pattern facing up on top. Use a red or blue ballpoint pen to trace over the desired pattern. You will want to use something other then a black pen so you can see where you traced. If you don't have a chalk coating on the back of your pattern you will want to push down hard to make a visible indentation on the black scratch art paper.
Young hands can get weary.
After this process is complete, remove the top pattern and untape the black scratch art paper. Without chalk you will have to hold the scratch art paper to the light and see your indentations. Otherwise the pattern will show in chalk. Scratch out your outline completely. You may want to do this in several sessions.