Select "Backup Schedule" down the left hand side. On the right you can either edit the current existing schedule by clicking on it, or "add" a new one.

If you select on your current schedule you will see information similar the the below. You can change the name of the schedule and the time it runs from. You also have the option to set a time limit on the backup, by changing "Stop" to "after" you can fill in how many hours you want this particular schedule to run for - this may result in unfinished backups depending on your internet speeds. From here you can also delete the schedule. Once you have made the changes you require press "ok" bottom right, and then "save".

If you select to "add" a new set you will see the below window, very similar to the above but here you will be able to select the backup "type" which allows you some control over when you would like the backup to run. Selecting "Daily" means the backup will run every day of the week.

Selecting "Weekly" allows you to pick which day of the week you wish for the backup to run on.

Selecting "Monthly" allows you to select the date it runs each month, or to select a specific recurring day.

Selecting "Custom" will give you the option to select a one time backup for a specific date at a specific time.

When you have set the schedule you wish press "ok" bottom right and then press "save".