Photos of the process of making a spatchcocked chicken
How to spatchcock a spatchcocked chicken:
Make sure to place the chicken breast side down and the thighs towards you first.
Use a good pair of kitchen shears to cut along each side of the backbone, cutting through the rib bones as you go.

Open the chicken up and flip it over, then flatten the breastbone with the palm of your hand, pressing down (see video) so that the meat is all the same thickness.
Season well on both sides with your favorite poultry seasoning and roast in the oven as directed in the recipe or grill for 15 to 20 minutes per side, depending on the size of the bird.