You do not need much for a class here, and you certainly do not need to buy anything before your first one. Here is the whole list.
Bring
Clothes you can move in. Anything loose or stretchy that lets you fold and reach. No special kit, no logos, nothing that has to be new.
A water bottle. There is a tap by the door to fill it. Nice to have, not essential.
Socks for after. The floor is warm oak and bare feet are best on the mat, but a pair of socks is good for the walk out.
Leave at the desk
A full stomach. Eat a couple of hours before, not just before. Folding forward on a heavy meal is nobody’s friend.
Your phone. The room is a good place to be unreachable for an hour. There is a shelf for valuables by the door.
The studio covers
Mats, blocks, bolsters, and somewhere to leave your things. So if you turned up with nothing at all, you could still take the class. Genuinely — people do it all the time.