For each backup shown, you can edit it's settings by clicking on the link in the Destination column, or remove it by checking the box on the left and hitting the Delete button.
To run a scheduled backup right now, click the Backup.. link on the right to bring up the backup form with it's details filled in. Or to restore the most recent backup made using this schedule, click the Restore.. link. In both cases, you will have a chance to confirm what is to be done before it goes ahead.
You should not schedule multiple backups for the same domains that run at the same time, as they may interfere with each other or run in an inconsistent order.