Somebody teach him how to pull up

If you go to the horizontal bars every day and pull yourself up at least 10 times, then your body and health will thank you very much. Cheerfulness, strength and pumped up muscles will be guaranteed. But it is important not to forget about technology. If you do everything wrong, then you can get injured. So somebody, please, just explain to this guy what he's doing wrong. Well, who's pulling up like that?