Start by soaking the cedar plank in water for 30-60 minutes.
While cedar plank is soaking, marinade salmon fillets as well. To do that combine marinade ingredients in a zip lock bag, mix them well and add salmon. Move air out of the bag and close it. Let salmon marinade while cedar plank is soaking.
While cedar plank is soaking and salmon is marinading, prepare the coals and preheat the grill. (Or, simply turn on the gas grill to peheat it.) Grill temperature should be around 400-425 degrees.
Place salmon fillets on the cedar plank, skin down. Save the marinade.
Place cedar plank on the grill and close it. Let salmon cook until just done. Depending on the thickness of the salmon, it will take 18-25 minutes.
For marinade: you can cook the marinade to create sauce for topping off salmon and you can cook it on stove top or on the grill. Let it simmer for about 10 minutes.
Spoon some sauce over the top of salmon while it's cooking, about half way through the cooking and towards the end.