Preheat the oven. Set your oven to 350 F
Prep your turkey. Make sure your turkey is fully thawed, plastic is removed, bags of giblets are out. If your turkey is not totally thawed I have tips below for dealing with that. Don't worry I'm always having to deal with a partially frozen turkey.
Pull the skin away. Gently run your hand understand the skin of the turkey to pull it away from the meat without ripping the skin. I usually do all of this prep work on a jelly roll pan or large cutting board.
Coat with butter. Soften the butter and mix in the chopped garlic, dried herbs and chop up any fresh herbs you want. I typically just use dried plus butter for this step. Using your hand, yes this can be messy, grab your butter mixture and slather it all over the turkey under the skin. No need for perfection, just do the best you can.
Season the skin of the turkey. Sprinkle a generous amount of salt all over the turkey skin. This will depend on your family's tastes. Treat it like you are season that amount of meat. If you are using garlic salt use half garlic salt and half table salt. Add a light sprinkle of pepper and then top with the smoked paprika.
Chop the veggies. Core the apple and chop into halves or quarters. Quarter the onions and chop the celery in 2-3 inch pieces. Take 2 pieces of celery and one quarter each apple and onion and chop into smaller pieces. This will be for inside the turkey. The rest will go under the turkey and help to lift it off the bag.
Season the inside of the turkey. Throw a generous pinch of salt and pepper inside the turkey. Add some chopped up celery, apple and onion and fresh herbs (or a couple pinches dried herbs). This is not stuffing this is just for flavor. You don't want to fill the turkey cavity make sure it is spread out and has breathing room. You want it only about 1/3 full so a totally of 1/2-1 cup filling stuff.
Prep the pan. Place the roasting rack in the pan then place the bag opened up on the pan, add in 2 TBS flour and shake around. Then add in the apples, onions, and celery. Spread along the bottom. you will place the turkey on top.
Bag the turkey. Add the turkey into the bag and seal with the plastic closure that comes with the bag or tie with a string. Snip a few holes in the bag along the top making sure to have a hot by each breast in thigh where you can insert the thermometer when it is time.
Bake. Stick the turkey in the oven and bake. Test for doneness. Remember that the turkey will continue cooking when you remove it from the oven so I take it out when it reads 165 F in the breast or 170-175 F in the thigh.
Let it rest. You only need to let it rest 15 minutes in the bag. Another awesome perk. You can let it rest for longer once you remove the bag if you need more time before you are ready to eat though.