Place the cedar plank in your sink or a pyrex dish, cover with cold water, and allow to soak for 1 hour. Place a bowl or brick on top of the cedar plank to keep it submerged in the water.
Place the whole salmon filet on top of the cedar plank and sprinkle with salt and pepper.
Heat one side of your grill, and place the cedar plank on the unheated side to cook your salmon over indirect heat.
Close the lid of the grill, and cook the salmon for 20 minutes.
Remove from the grill and serve. Discard the cedar plank when finished.