baritone is correct. you are thinking of a side hill lie below your feet - aim left as it will go right. conversely a ball above your feet - aim right as it will go left.

On a downhill shot you want to try to get your shoulders to be parallel to the ground and swing down through the ball along the slope of the hill. This helps to avoid topping or duffing the ball. It is still a more difficult shot than flat or uphill lie, but plan on more roll, or take less club, as you are delofting the iron on a downhiller. Good luck.