 If he gives you his paw, you click. It's like taking a picture of the exact behavior you want to reinforce. You actually click before you start giving the dog a command or a hand signal. The first couple of times you just wait for your dog to sit, then you give him a quick click and a treat. When your dog gets clicked several times for sitting and starts to repeat the behavior knowing exactly what earns the click, you can start using a hand signal or the word sit. A clicker will help you be very clear in the behavior you want from your dog. Be patient. And remember, good boy.