Firstly you need to get yourself an FTP client, FileZilla will do the trick.
- Log on to ClanForge.
Click on your server name, or the small, blue "Manage" button to the right of the page.
- Click the "View FTP Details" button in the far left hand menu.
You can now see all your FTP credentials, If you only want to browse your space or download a world backup you can hit the big green "FTP to this server" button and that'll load up a web-page from which you can navigate into the backups section and save everything locally.
- In FileZilla navigate to your backup in the left panel and navigate to the backups file in the right hand panel.
- Drag the backup form your PC on the left hand panel to your server in the right hand panel.
- Go to the "World Management" tab on ClanForge.
- Choose your backup from the list. (sorted newest at the top)
- Hit the yellow "Restore a backup" button.