From the main screen, click the logo in the upper left corner, and choose ‘Server list’.

In the server list, click the ‘Add server’ button (), and choose ‘Manual’.

Then enter the connection information in the fields as explained here:

• Display name: A simple name for yourself to recognize the server. This has no effect on the connection at all.
• IP address: The IP address of your server.
• Port: The port number your server is configured to listen at.
• MAC address: This field is not required. The MAC address of your server, used when using Wake on lan.

If you don’t know how to find the information you need to enter, see this FAQ entry.