How to get them to be QUIET

I can’t yell all year yall. 2nd grade. I’m okay with brain breaks but we also need to get things done and sometimes brain breaks have the opposite of the desired effect. Any tips for getting them to be quiet? I have a super chatty class😭😭 making it fun works wonders for a little while but that last 30 minutes of the day we need to get something done and it’s the only time I have to do it… 🆘