They give you 4 sets of buttons. I believe one metal looking, one black, one khaki, and one grey. The buttons are in two pieces. You are supposed to hold the button with one hand, and with the other hand push the back in and pull it off. This exposes a pointy tip that you can insert into your jeans and then put the backing on to hold it tight.
I could not get the back off! Everything is so small, it's hard to get an adult finger on it. Somehow the back of the button piece broke off. What a fail this product is. I'm returning it to the store.
People on the web report having to use a pair of pliers to get the back off, and to get out of their jeans. Who the heck wants to carry around pliers to go to the bathroom?