This might help : Haynes Guitar Books
I have the Stratocaster one and found it full of great info.
The guitar books are intended as a bit of 'uselful humour', I guess - if you haven't heard of Haynes, they're a part of the home auto mechanic's folklore (in UK at least):
Historically, from the 1960's, Haynes manuals have provided great information on how to maintain cars - one manual per model of car - stuff like how to remove the engine, overhaul brakes, set valve timing, etc.
A pretty major resource.
Obviously the range of manuals is huge, covering most cars back to the 60's.
Some of the older manuals are now quite valuable.
Recently they branched out
- you can get a Haynes manual for the USS Enterprise (maintenance & repair) and also how to maintain your wife / baby and Supermarine Spitfire - clearly intended as a joke but they often contain useful info.
OK maybe not in the USS enterprise one haha
However I have the Stratocaster manual
and it's very informative and goes through the kind of thing you're talking about.
I'm guessing the general
Electric Guitar one is just as good, just more generic.
I'm assuming here you mean electric guitar, but if acoustic, a lot of the same principles will apply.
Alternatively there may be an acoustic manual..
music.stackexchange.com/users/7337/user2808054
If you can find a luthier locally, you might be able to convince them to let you observe them working, especially on your own guitar - maybe even guide you to do the fixes yourself.
You could certainly ask your friendly luthier for advice how to learn, or at the very least how they learned.
music.stackexchange.com/users/15313/Mr. Boy
If you are willing to buy a book, this is the indispensable reference: http://www.danerlewine.com/guitar_repair_books.html
The guy's a god, and it covers everything from how to string the instrument to insanely complex repairs like neck resets and fixing holes in the side...
music.stackexchange.com/users/9337/Robert Fink
I found this author extremely helpful.
His basic guitar setup is one of the indispensable books i used to learn.
http://www.amazon.com/Hideo-Kamimoto/e/B001KHY1WA
Here's another even more basic but good book.
This one touches on both guitar and amps.
http://www.amazon.com/The-Complete-Guide-Guitar-Maintenance/dp/0793534909
If you have a cheap beginners guitar to practice on you'll sleep better at night, but keep in mind the cheaper they are, the harder to get to play right and you'll be working for nothing.
But that's better than stripping the threads off the truss rod nut on a good guitar!
music.stackexchange.com/users/13768/user6591
Get yourself a second hand guitar, broken or not.
Cheap is good.
Then use it as your guinea pig.
Chances are you won't break it, but when it ends up as a real playable instrument because you've fettled it by yourself, it'll be a great feeling.
If the worst comes to the worst, it's cost you very little, but given you great experience!
music.stackexchange.com/users/2808/Tim
There are several instructional DVDs available that go through the entire flow of setting up a guitar.
Here's one example after a quick search: http://www.amazon.com/Guitar-Setup-Maintenance-Instructional-Denny/dp/B002I9PSQC
music.stackexchange.com/users/13674/FDM
Your best option is to find a local luthier/guitar tech that is respected and ask to apprentice with him and learn everything you can.
Other than that, there are some schools that teach guitar tech.
One
I know of is the Musicians Institute: http://mi.edu/degrees-programs/industry-programs/guitar-craft/ That being said, you can also do what others are suggesting (and what I did) and just experiment on your own guitars and learn what you can from the internet.. there is tons of info out there about guitar maintenance and construction.
music.stackexchange.com/users/13110/Charles
I have watched countless Youtube videos with very little luck whatsoever. The information out there is so scattered. I am asking, is there a way I can learn to work on my guitar that is very simply stated? I want to learn to set the neck, adjust action and string height etc. Thanks
Where can I go to learn how to fix my guitar?
music.stackexchange.com
<electric-guitar><repair>
music.stackexchange.com/questions/27485
music.stackexchange.com/users/16809/Jordan
Finding a luthier locally, and asking them to let you observe them working, especially on your own guitar - maybe even guide you to do the fixes yourself - is one way of learning to fix your guitar. Otherwise, for books the indispensable reference is:  http://www.danerlewine.com/guitar_repair_books.html. There are also several instructional DVDs available that go through the entire flow of setting up a guitar.  Your best option will probably be to ask a local luthier if you can watch them and learn from them. Otherwise, there are instructional books or DVDs available that may be able to teach you what you need to know.
Your best option will be to find a local luthier and ask if you can observe them working to learn from them. You could consider buying an instructional book or DVD to learn from.