To suspend (and later resume) a backup schedule, you need to do the following:

Go to the List of Backup Schedule page.

In the column titled "Action", you will see a suspend/resume icon for each backup schedule listed.
Clicking on the suspend icon will suspend the backup (and the icon will change to ‘resume icon’).
Clicking on the resume icon will resume the backup and schedule it as per its schedule. However, a resumed backup will also run once immediately and thereafter as scheduled.