Welcome to the Forum @paul-Korean-A1_Beginner_TOPIK
Yes, there are not so many Korean students in the system yet, so many of the group classes for Korean are actually just one student. Thats of course great value by paying for a group class and getting a 1on1 class, but I fully understand that you want to study with others together in a group. Its often just more fun.
When you book a class, you can see how many other students are in the class by checking the number next to the seat. The maximum seats available are 5, so if the number is 5 then there is currently no other student booked into the class. If the number however is 4 for example, there are only 4 seats left, so there is someone else in the class.
When you click on Class Details you can also see who else is in the class. If you click their profile and they are on the forum, you can click on it and see a list of all their upcoming future classes too (or contact them to say hello)
The best way to meet other people studying a language is actually this forum. I myself started studying with another Vietnamese student after she made this post
Make a similar one for Korean and let people know you would like to study together and they can then join your classes by clicking on your profile picture and see your upcoming classes (or you theirs)