The installation of x2go client should be performed in accordance with the manufacturer's guidelines: http://wiki.x2go.org/doku.php/download:start
During the first activation you should create a session using wizard:
Type the following data:
Host address IP or the host name of your server, e.g..184.108.40.206
SSH port 22
Session type Choose "Custom desktop" from the list and manually type "gnome-session --session=gnome-classic".
This is all the data that needs to be typed in. If the connection is poor you can change "connection speed" in the bookmark "Connection" or picture quality.
Click on OK to save the session.
To connect to the server click on the icon of the session created in the right corner, and then click on OK. Now type in the password and click on OK.