This instructions are only for the backups on the remote server.
To Enable remote backup in your CWP.admin go to CWP Settings --> Backup Configuration

You will need to enter the login details into the fields of "Remote Backup Settings"
Don't forget to generate the new remote access Key.

On the remote backup server you need to add the pub key
cd ~USERNAME
mkdir .ssh
chmod 700 .ssh
nano .ssh/authorized_keys
Now add all content from the file /root/.ssh/backup/id_rsa.pub to .ssh/authorized_keys
chmod 600 .ssh/authorized_keys
chown -R USERNAME:USERNAME .ssh
chown USERNAME:USERNAME .ssh/authorized_keys

You can use test connection button in CWP.admin to check connectivity with the remote backup server.

To connect and check content on the backup server you can use ssh key access:

ssh USERNAME@SERVER-IP -i /root/.ssh/backup/id_rsa -p 22