It is always fun to bomb a tee shot then find yourself on a downhill slope. Most players will struggle with this shot and top the ball more often than not. What I tell my students is they have to get their shoulders and hips on the same line as the slope. Once they get the feel then when they swing make sure they swing down the slope. When we get set up we also discuss what the slope will do to the loft of the club. It decreases so the can use a less lofted club and still get decent distance.
Always keep it smooth and keep your weight a little more toward the foot that is higher. So in this case back foot.
Good luck