You just kind of... do it.

Step 1.) Pack what this dude tells you to and follow his advice for food -- http://www.adventurealan.com/best-backpacking-food/

Step 2.) Go when temperates are cool at night, but not cold (high 40F as a minimum). This allows you to buy cheap gear to learn with.

Step 3.) Pack the gear this guy tells you to -- https://itunes.apple.com/us/book/the-ultimate-hikers-gear-gu...

Step 4.) Buy the cheapest lowest quality gear you can for cool weather hiking. Let it be heavy/used/whatever. Cheap shelter. Cheap sleeping bag. Cheap pack. Except -- https://www.traildesigns.com/stoves/caldera-keg-f-stove-syst... learn about alcohol cook systems. They are super light and there is no sense in buying a heavy cook system you will just re-purchase. For a pad, just get a foam ridge rest, see if you can live with it. Most thru hikers end up with a very minimal padding. Something like a thermarest prolite is an okay compromise if you can't stand a ridge rest foam pad thing. There are some ultralight air mattress options that aren't too heavy, but foam pad is easiest.

Step 5.) Plan very low risk "backpacking" at state park camp grounds where there are RVs and lots of people. Trial your gear. If you fail you are right next to lots of people and shelter. Go to places with lots of day hikes. Hike all day. Camp at the camp ground at night.

Step 6.) You should know what kind of sleeper you are. Now you have to decide... are you a camper or a hiker? If you are a hiker, be a gram weenie and buy the nicest ultra-light gear you can afford. If you are a camper, stick with comforts, plan to hike less. Check out cottage gear makers like enlightened equipment and z-packs. Their gear is great. Pay attention to skurka on water treatment: platypus plastic bladders are fine. Aqua mira (a chlorine water treatment system) is super easy.

Step 7.) Do the things. After 3 or 4 weekend trips you will start to know what is up.

Step 8.) Keep reading the blogs and gear things of crazy ultralight hikers. Expand your horizons. If you hike more, learn more about ultralight gear (http://www.adventurealan.com/2-4-pound-extreme-ultralight-ba...)

Step 9.) Learn about orienteering and navigating with map and compass. On major trails you can get away with guide books, but a little knowledge can help you out here.

Step 10.) If you are athletic stick with "trail shoes" and not hiking boots. Hiking boots are crazy. I have hiked hundreds of miles on the AT in plain old running shoes. buy nice wool socks. Accept your feet will be wet and that it is part of the experience if you are a distance hiker. Wool socks will keep your feet warm, even if they are wet :)

You will make mistakes. Surprisingly a lot of the rules of how and where you can hike are very sparsely documented outside of the main trails like the AT.

That is it. Start safe to permit mistakes. After a week of nights outdoors you will have the hang of it. You can start planning weekend backpacking trips then probably.

These are all just guidelines. I am not sold on any brand or whatever, I just use these things and know they work for me. You can spend endless hours researching gear. You just have to commit, be safe, and learn what works for you and what you like and enjoy about the outdoors and backpacking experience. Some people love camping and food and hike as a means to see beautiful places. I am a restless soul and want to tire myself out covering ground when I hike. I am there to be in motion in nature. You just gotta think it thru and figure what you like, and if you like it.

Good luck! Happy trails.

edit: I have met thru hikers that literally had /zero/ experience when they started an AT thru hike. By the time they made it about 50 miles on the trail they are throwing out hatchets, heavy foods, and heavy gear. If these folks can do it, you can to, and you can cut out the days of misery as you learn your gear is too heavy, etc.