Hi!
At the moment this would need to be done by adding a backup job (which is just a cron job [1]) manually to /etc/pve/vzdump.cron. Note that backup jobs created through the GUI are stored here too, so if you want a template, just create a daily backup job for the container in the GUI, with e.g., start time 12:00, then in /etc/pve/vzdump.cron, you just need to add a second hour to run the job by adding a comma and value (e.g., 12,20) in the hour column.
You can see the admin guides section on adding PBS storage [2] and backing up data [3] for more information.