The following is from the Nesco site.
Guidelines for cooking a Turkey in the Nesco 18 Qt. Roaster.:
Thawed Turkey, Poultry Seasoning, salt, pepper, 1/4 cup margarine (melted), 2 tsp. browning sauce.
Place turkey on rack. Combine marg. & browning sauce; brush turkey. Sprinkle on seasonings. Preheat to 400ÂºF. Cook at 400ÂºF for 1st and final hour, remaining time at 350ÂºF. Total cooking time 15 to 20 min. per pound.
Personal note: The past three years, I've always brined my turkeys for 24 hours. For that size bird, I'd brine with 1 gallon of water/ice, one handful of salt, one handful of sugar, whatever herbs and spices you like. I like rosemary and thyme.
Boil half the gallon of water to dissolve the salt and sugar. Add ice to bring the volume up to 1 gallon. Place turkey, breast side down, in doubled plastic bag sitting in a big bowl that the turkey will fit in. A big salad bowl usually works well for this. Pour the brine solution over turkey. Seal bags. Refrigerate for 12 to 24 hours. One hour prior to roasting, dump out the brine and fill bag with tap water. Drain and let turkey sit until you're ready to roast. DO NOT add any additional salt to the turkey prior to roasting. I just rub the turkey with oil and sprinkle with pepper. I also stuff the bird with aromatics (unpeeled onion, celery with leaves, unpeeled carrot cut into several pieces).