Card creatures monopolize land. Invade or pay the toll.
Here are the basics:
Resources are gained by passing castles and earning tolls.
Land is claimed by placing card creatures, which cost resources.
When a player lands on a space owned by an opponent, the player must either pay a toll (consisting of resources and points) or successfully complete a card battle invasion.
Victory points are gained by owning land and earning tolls.
Pass a castle with enough victory points and you win!