Settings > System > Backups: Secure FTP: You set the time you wish to do it (hourly / daily)
Settings > System > Backups: Amazon S3: You set the time you wish to do it (hourly / daily)
And it will be done when you set it. Once a day I would assume it's midnight. I have every 12 hours on FTP and it works for me.
If it doesn't work (try testing the connection, it might be the port is closed or the IP is blocked in the firewall.