In your connection manager open a connection to get started.
Note: If you need SSH capabilities on one of these connections, open this connection as the first primary connection in order to use SSH during a server to server connection.
On the local side, click on the blue "Change" button, a dialog will then appear to make a new filesystem selection, click "Server to Server".
A connection manager dialog will be displayed after choosing "Server to Server", simply select your connection choice.
Just like a local to remote connection, simply upload or download files and folders as you would if you were to and from your local device.