@vivianaj I spent a few minutes looking for threads here that are similar to yours. Here is a link to one that was highly active until the end of 2021 — https://www.sellercommunity.com/t5/Read-only-archive-Square/Feature-Request-Schedule-classes-group-s...
From what I can tell, you can NOT currently book multiple clients into one appointment slot. Various people requested such functionality, and it looks like Square was active in that conversation. So it seems they are aware of it, but I can’t find out anything more. I will say that since I don’t see a subsequent announcement by Square that this feature exists, I’m pretty sure it does not. It MIGHT be in the current beta test for Appointments, so I’m going to tag @kellyj here so she can either reply here or private message you if it does. If it does you might be able to join the beta test (though, not being a Square employee I CAN NOT guarantee that one!)
I’ll leave you with one other possibility. Here is a link to a help article about Square and Events App — https://squareup.com/help/us/en/article/7501-event-app-and-square
Might you want to consider setting up your classes as events, instead?
Best wishes,
