Install x2go on the laptop/PC. You need X and SSH on the server. That's it, when you connect it will open a new desktop session on the server.
If you want to connect to an existing desktop session you need x2godesktopsharing installed on the server, you need to activate sharing in x2godesktopsharing, and in x2go client (on laptop/PC) you need to select "session type" as "X2Go/X11 desktop sharing".