The online drawing scene is interesting and worth looking at.
I stumbled into it when I was searching for live figure drawing locally, using Evenbrite. I found more happening online via Zoom than locally. There are lots of live sessions in London but that is too far for me now I've moved to the countryside.
The way it generally works: a host manages payments, books a model, plans the session with the model in advance, sends out a link and guides the session. Any number of people can join. There are usually rules to restrict sharing of the images due to the nudity and the copyright of streamed video.
Sessions are of varying lengths and mostly a model is featured for a couple of hours. Sometimes there are several models one after another. There are rest breaks for the models and the poses are generally timed, starting at around 5 minutes long and going up to 20 minutes.
Once or twice a year some hosts run marathon sessions and you can draw all day from lunchtime, into the early hours of the morning.
I have to go out now so I will need to finish this window view of the online scene later on.