To brine a turkey you will first need a large, nonreactive container. This could be plastic, glass or stainless steel. Other metal containers will react with the brine solution and give the turkey a metallic flavor. One great trick is to use a large, food safe sealable bag. Both Reynolds (Oven Roasting Bag for Turkeys) and Ziploc (XL Storage Bag) make very large food safe sealable bags that are great for brining. I prefer the Ziploc bags because they are stronger and less likely to be punctured. Place one of these bags in a large stock pot. This keeps everything together and makes clean-up easier.
Next is knowing how much water you are going to need. To find this out, place the turkey, still in its packaging, in the container and fill the container with water. Yes, I know that the turkey is basically hollow so, add a few extra cups of water later when you do the math. Next, figure out how much water it will take so you know how much salt and sugar to add to the brine.