The GOG version will not have an 'online' component until GOG Galaxy launches. For now, multiplayer is restricted to LAN (button at the top of the Join window beside 'Online') or Direct Connection (IP address or Server ID).
If you have the Steam version (and the client is running), you should see lobbies in the Join screen even if you have your own 'Online Game Visibility' set to offline (in the Game section of the options).
You can also check your settings in-game in the Connection Menu (diamond icon top of mini-map).
Global chat was disabled until Larian can add some better
moderation options and make it
slightly less global (I would assume setting up different language sections).