Personally I would have a quick look through books, not marking as such, a literal flick through to see where everyone is. I’d then write a plan of action.
I’m an Art teacher so when I need everyone up to speed they get one hour, I’ll have a checklist on the board and 2/3 tasks going:
Group one: you’re finished ‘task A’ therefore you will do ‘task b’ use your tablets to access this tutorial (I used to print off help guides before we had one to one devices).
Group two: ‘you need to finish these elements of ‘task A’ once you’ve finished you need to start ‘task b’ following the instructions above.
Group three: ‘you were absent and need some input from me, gather round the front for a quick tutorial. You’ll then complete ‘task A’ this hour.
I can then start afresh the following lesson with everyone in more or less the same place. If it’s a GCSE group and there’s still students who are not finished ‘task A’ it then becomes an intervention time (am reg for us) problem. This encourages the kids to take a bit of ownership when they miss a lesson too.
It takes a bit of practise and it’s really important that you do two things:
Ensure ‘task b’ is an extension task that the kids can be supported through using a PowerPoint or help sheet without too much input from you. It’s a bonus if it’s revising a previously visited topic OR is something where it’s not the end of the world if they don’t finish it.
Be VERY clear with your expectations in terms of how long they have, the fact you’re moving on next lesson regardless and any talking that’s going on whilst you’re giving a tutorial.
Once you’ve got it running in your classroom the kids will become familiar with the process so when you do have to have a lesson where there’s different groups doing different things they’ll know what they need to do.