Step 1: Materials
-A sheet of lined paper
Yes, you heard me right. Only a sheet of paper. But for best sound (loud), then go with paper that's thinner than blank paper, since it needs to unfold really easily. Kind of like Magazine Paper.
Step 2: Folding the Paper
After getting your suitable paper, create a small fold at the bottom, and continue folding up, until you have a open space at the top...
Step 3: After Folding the Paper Up...
Step 4: Folding the Paper Again
Step 5: Firing it Off!
After the paper cracker has been "fired off", you should notice that part of it has unfolded down. Refold it up, and repeat step 4. That's how you "reload" it.
Yours not working? I can probably tell you what's wrong. Leave a comment if you're having trouble...