You just hold it up to your eyes so that the upper eyelashes are between the rubber pads, then squeeze the handles together. Go gently at first to make sure you haven't accidentally caught some of your eyelid in it. Then squeeze the curler with fairly good pressure. I usually count to 8 or 10 before I let go, but my friend told me she doesn't hold it at all. Then open the curler and take it away from your eye. You have curly lashes! Apply your mascara, and you are done.
If anyone knows more about this, I'm willing to learn, but I think that's pretty much all there is to it.