The gameplay takes place on a grid. The game's characters move at the same time, rather than manipulating each entity individually.
Another feature of the game is called the Zone of Control. The Zone of Control means that if the player's character is next to his opponent's square on the grid, they must stop and fight. By using the Zone of Control, combined with simultaneous movement, the player can trap an enemy unit.
The player eventually gets to control a handful of heroes who progressively get more powerful. These are combined with a number of warriors. The user may play as the Fellowship or the minions of Sauron.
Source: Wikipedia, "The Lord of the Rings: Tactics", available under the CC-BY-SA License.