You don't have to be an avid hiker to go backpacking with your dog. It's a great activity for the both of you and many dogs are quite happy to have a job while out on a walk with you.
Most importantly, as with starting any activity, have your veterinarian check your dog over to make sure she is healthy. Secondly, you're going to need to purchase a dog backpack. One made for humans just won't do. You can buy them at pet stores like Petsmart or Petco or at many online retailers. Make sure it is the right size for your dog (most packs list a weight and a girth on the package).
Once you get the backpack, fit it to your dog. Adjust the straps so that it fits comfortably but isn't too tight or so loose that it slides around. Remember, your dog hasn't worn a backpack before so it will take some time for her to get used to it. The first time you put it on, don't leave it on long. A minute or two at most. Have your dog wear it for a couple brief sessions before you take her on a walk wearing it. On your first couple walks, the pack should be empty. Let her get used to wearing the pack before you add weight to it. After several walks with an empty pack, you can start adding some weight. Keep it light to start, then gradually increase it.
Pretty soon, you won't have to carry any of your dog's accessories when you go walking. She can carry her own water, dish, toys, leashes, and poop bags. She can even carry some of your stuff too! Just remember when packing her bag to keep both sides of the pack approximately the same weight. It is very uncomfortable to have a lot of weight on one side and very little on the other. Also be sure to keep an eye out for sores that the pack could cause.