Is there a minimum or maximum number of clients I can take on?
This depends on your own capacity to handle your workload and is your decision. Some therapy assistants are happy working with one client, but there are others who can manage multiple clients with full-time study.
If you would like more hours you can elect to take on more clients. But is essential that you don’t over-commit or promise to work with clients when you don’t think you could commit to working with them for at least 6 months.