First you need to use the hammer and nail to punch holes into the to of the bottle caps. DO NOT MAKE THE HOLES TOO BIG. Just a small tap will do. Just enough to make a small hole about 2mm big, it doesn't matter if its 3mm or 4mm.
Once you have done about 60 aprrox. then you can get out the elasticky stuff!!!
Start by threding the bottle tops onto the elasticky stuff. do this untill there is enough on the elasticky stuff to fit your wrist.
Finish by tying the two ends together or you can alternativly use these kind of metal beads that you can crush so that it acts like a stopper.