Pre-heat half your grill to medium-high and place the cedar plank on this side of grill, pre-heat other side of grill to medium low. Wait about 5-7 minutes, or until nice char marks appear on the bottom side of the cedar plank, some black spots are good, but don’t char it too much. Turn the plank over to the un-charred side, and move it to the cool side of the grill. Place the fish on the cedar plank, lower the hot side of the grill to medium low, close the lid to the grill, and cook for 18-22 minutes. Salmon will over-cook easily, so check it with a fork, and if it flakes off easily it’s ready, or just cut the fish in the middle and see if it’s done to your liking.