Territories is a game mode that revolves around capturing and holding a set of points in order to increase your team's victory points. You gain a ticket every 2/5 seconds (depending on if the map is 3 points or 5 points) for every point your team currently controls.
Destroying enemy vehicles (on the ground) / capital ships (in space) will decrease their tickets, relative to the strength of the vehicle.
The game ends when a team has scored enough tickets (based on the "minimum game length" setting of the server) to win.