At My Online Therapy, our psychologists manage their own schedules. They usually update their upcoming slots a minimum of 2-4 weeks in advance. Psychologists can also reserve sessions for you which allows them to save the specific date and time and they can then change that to a booking in advance of the session which will trigger the payment method to confirm it. There are many options available for booking in and reserving upcoming sessions, so please do discuss in your therapy session.
Please note that psychologists release sessions in slots of 30 mins and 60 mins, so if you are looking to book in a 50 minute video call, for example you will only see times that are available to accommodate sessions of that length. If you see availability on other days, but no times slots this is most likely because they are only open for 30 minute sessions.