How can I change when my clients get their reminders

You can easily adjust how far in advance of your client's appointment that they will receive their email/text reminder.

To do this, click on "Settings":

Then click on "Booking Settings":

Then you can adjust how far in advance the reminder goes out by clicking on the drop down menu:

A new window will appear and you can select your length of time and click "OK":

Then save it at the top right by clicking the "save" button: