The Scheduler feature currently allows students to make appointments immediately after an appointment group is set-up and published. Appointments are immediately available on the Calendar and students are informed via Canvas.
This idea is to allow instructors to set an additional "start time" so that all students can only begin to book appointments at that future "start time". Students should also be sent the appointment information at the onset of the "start time".
The current situation is not always desirable because I use the Scheduler feature to allow students to book presentation session times that are staggered throughout the semester. Having a common "start time" to make bookings makes it fairer because some time slots can be better than others (earlier versus later sessions etc.).
The way I get this done today is to announce a common start time in advance, and then create the Scheduler group near to that exact time. This is a clumsy approach because it does not allow me to setup a Scheduler group in advance. Some Scheduler groups can be complicated (with multiple dates and times), and having to do it on the fly does not allow me to check for errors. Having the ability to restrict students' bookings until a certain future time makes the Scheduler tool easier to use because appointment groups can be set up in advance and checked before students can access or use them.