So, you've set up your streaming solution, and made the smart decision to use a class management/booking system to manage your live streamed classes and increase their visibility. Now you need to provide the participants with clear instructions about how to access your classes, which can feature in your class description:
Tell them what platform you're using to live stream (e.g. Zoom, Facebook Live, etc).
Tell them how they can access the class (e.g. you'll send them a link via email 10 minutes before the class, they'll get the live stream link in their confirmation email, etc).
Tell them how ready their technology for the class (e.g. download the Zoom app in advance, make sure you can log in to your Facebook account, etc). This could also include making sure they have a fully charged phone/laptop, have a safe space to workout, what equipment they'll need.
Tell them if there are any expectations on them (e.g. do you expect everyone to keep their own camera on so you can provide feedback or do you not mind?).
Tell them what time they can access the class from/until and if you'll be available before or after the class to answer questions or just to chat (it's important at times like this to make real connections!). Alternatively, make it clear if you don't want participants to join before the start time of the class - important if you've got back to back classes using the same live stream!