Revest will run the backup depending on the backup frequency or backup schedule that you have set in it.

If you have decided to run Revest at certain schedule, then Revest will use Windows Task Scheduler to achieve that. So, if you want to set Revest to run once a month:

Open Revest→ Settings → Schedule → Select the option On schedule and set any day and time to start the backup at → Save the changes.Or if you have assigned a policy to this user, go to this policy → Settings tab → Backup Schedule and set any day and time to start the backup at → Save the policy.
Now, on your machine go to the Start menu → Control Panel → Administrative Tools → Double click Task Scheduler.
From the left panel of the Windows Task Scheduler, select Task Scheduler Library.
Double-click the Revest Start Backup task from the list of your scheduled tasks.
From the Triggers tab, select the trigger that appears there and click on the Edit button.
From the window that will appear select Monthly and from the Months drop down menu select all the months and from the Days menu, select the day that you want the backup to run at.
Save the changes.