Thank you for the information. I went and had a look.

There do not seem to be any obvious physical features correspondinng to these classes on the ground, so I couldn't update the map for you as part of the survey I just did

If there's a postal address associated with your classes, you could add that information as node within the building, if it's a unique street address https://wiki.openstreetmap.org/wiki/Addresses

Otherwise, perhaps you could look theough the list of features https://wiki.openstreetmap.org/wiki/Map_features#Art,_music,_hobbies for something that's suitable to be added? Remember, OpenStreetMap maps physical features (mostly, since addresses and opening hours are additiona data that isn't strictly physical).

Right now, it would be useful to map the main entrance, or any studio side entrances (along with their wheelchair accessibility, nearby disabled parking etc.)

Do you just want to share pins and shapes on a map with people? https://umap.openstreetmap.fr/en/ has you covered!

Please read our https://wiki.openstreetmap.org/wiki/Beginners%27_guide getting started guide for further information.