The Rexburg Temple has been closed for a few months, but it will be reopening this week. There are still a large number of appointments available for all ordinances. If members are struggling to understand how to use the reservation site, you could direct them to this webpage that has both printed instructions with links and a video that walks you through the procedure step-by-step.
https://lds365.com/2021/07/02/how-to-schedule-appointments-at-latter-day-saint-temples/