Air-cooled portable air conditioners are intended to be rolled into a room near the source of the heat. For spot cooling applications, you point the nozzles at the spot that you want to keep cool. For room cooling applications, the nozzle direction is not as important.
Since the air conditioner is inside or near the space requiring cooling, you must duct out the warm air that the air conditioner produces. In an office environment this is typically done by ducting the condenser air from the top of the unit up to special ceiling tile that directs the air to the main building cooling system's return air plenum above the ceiling tiles.
As the cool air from unit offsets the heat being produced in the room, the temperature in the room will begin to drop. The capacity of the unit, the amount of heat being added to the room, and the size of the room will determine how much the temperature will drop.