My players keep getting distracted

My players keep getting distracted during each other's turns in combat when I'm describing things they think don't apply to them, pretty much all the time. I have tried various things, with iffy success rates. By the way, these are players aged 10-18(a couple of campaigns). They go on their phones, spin their dice like a top, and-especially the younger ones- they talk over me and others. This is more of a problem when I have a bigger group, since I play in a local restaurant that hosts a game night on Fridays. Also, how should I catch up players if they miss one or more sessions?

If it is a bigger group (6 or more) there is very little you can do. Once you get closer to 10 people than 5 you will naturally start having multiple conversations going on at once. I played in a group of 20+ year olds where there was 7 players and the DM and a decent amount of time we had the same thing and we all had much high patience, attention span, and self-control than your group.

You should still try to tell them to pay attention, but don't feel bad if you aren't very successful. Professional teachers often struggle to keep kids attention, you can't expect yourself to be able to keep them all glued to the game all the time. All you can do, is try to keep turns as short as possible and attempt to discipline them if they interrupt / talk over you.  Good luck!