You can specify the number of participants needed to run a session in the product description. For example, if you are hosting a group masterclass and require at least 5 participants, you should mention this. You can also limit the number of sales on a product in the ‘Inventory’ section of your Product Listing page. After all the slots have been filled for your listing, you should then contact the buyers to organise how to proceed with the session. 

Quick tip: Include a ‘last date to enroll’ in the description so slots can be filled over a limited period of time.