To start hand hooping, you're going to reach your hand out in front of you like you're going to give someone a handshake. Your thumb is up and out, so you're making this L shape with your hands, either your right or your left hand, whichever is more comfortable for you.
And you want to keep the hoop there in front of your thumb on the other side of you. If you allow the hoop to come on the other side of your thumb, then what it tends to do is, come up and hit you in the face. So, to avoid that, thumb up. Then you're just going to give the hoop a push, and there you go.
And I'm giving the hoop a little bit of momentum down and up, to keep it going. Then from there, you can put both hands together in a prayer position, and hand hoop on both hands. Remove the other hand. Switch hands.
I would suggest practicing switching from one to the other, until you get comfortable with it. And you can turn your body, so it's on the side of you.
And that's how you do hand hooping.