To knock them out find one put all your stuff in a storage bin get a bow/cross bow and tranq arrows to knock it out run and hit it with your bow/cross bow. To tame it just get any kind of meat you like and shove down its throat
Before my game got overrode I had two of these guys. They were absolute beasts, I would run around with them and farm supplies from dinosaurs. The best way to tame them is to him them once get on a flying mount get on high ground, and then pump them full of tranquilizers. They make great mounts too.