Goto cPanel click to open RvSitebuilder then in the top right corner there is a cogwheel. Cliick the cogwheel and select Backup Website link.
Once the backup is complete, click the download link and save to your computer. You should do this after making major changes. THEN DELETE Your backup files. They are still on the server they are located in the home directory, that's before the public_html. Then empty the trash. This will prevent excessive disk usage.
To restore website; open the cogwheel menu and select the Restore by Uploading.