Golf for the 2600 is a simulation of the sport, with similar rules.
To play the game, position your character near the ball. Note that you always swing the club in the same direction, so depending on which way you want to hit the ball you may need to move on different sides. If you start your wind-up and realize you're on the wrong side, move the joystick to step away from the ball. The longer you hold down the button, the further the ball will be hit.
You start out on the fairway, and upon entering the green, switch to a closeup view for putting. Hazards have different effects, so try to avoid water, sand pits, and trees.
By adjusting the game difficulty, you can choose whether the rough (area outside the fairway) is an impassible wall or not. True to golf, landing in the rough makes it harder to spot your ball and get out.