How do I teach my dog to sit using a clicker?

When I'm teaching a dog to sit, I use a hand signal where my palm is out and my forearms are at a right angle. I lift my hand up above the dog's nose with a treat in it. As you lift the food above the dog's nose, their nose is going to go up and their butt is going to go down. The second their butt touches the ground, I click with the clicker to mark that precise moment and give them the treat. Once the dog is proficient at the hand signal, you then would say a cue word, like "sit," a fraction of a second before you do the hand signal. Then you would start gradually fading out the hand signal.