You can schedule your message by selecting the "Based on Booking's Timeline" option. Then, choose how many days before or after a specific event (e.g. Booking Creation Date) the message should be sent.
For example, selecting "1 Day After Booking Creation Date" means the message will be sent one day after the booking is created.
Alternatively, you can choose "Right after all conditions have been met" if you want the message to be triggered as soon as the criteria you set are fulfilled.