Excuse me if I misinterpreted your post, but:
You can't read sheet music?
Then you're going to have to start learning, sir.
The musical staff is made up of lines and spaces, like so:
[url=http://www.spirit-lake.k12.ia.us/dist/forms/music%20staff.jpg]Picture[/url]
Because you'll be playing guitar, you will be reading the treble clef, which is the top row. The bass clef is the bottom row, which is for instruments like bass guitar (duh) and trombone, among others.
The lines and spaces of a treble clef read as so:
F
D
B
G
E
And the spaces, from top-to-bottom, are as follows:
E
C
A
F
There are a few mnemonic devices you can use to remember them, such as Every Good Boy Deserves Fudge, and FACE spells... well, face.
Ledger lines are notes written above the lines and spaces.
For example:
[url=http://img.photobucket.com/albums/v607/frozeninshadows/ledgerlines.jpg]These are whole notes on the bottom ledger lines[/url].
For each line/space, go up or down a value.
So, the full set will read as such [-line- and (space)]:
-F-
(E)
-D-
(C)
-B-
(A)
-G-
(F)
-E-
Of course, a lot of jazz has accidentals (flats, sharps, double sharps, double flats, and so on), so remember that:
Flat: lowers note by 1/2 step
Sharp: raises note by 1/2 step
Double flat: lowers note 1 whole step
Double sharp: raises note 1 whole step
///
In terms of chord construction, what you are going to have to do is, on your spare time, translate the notes into chord shapes, and then be able to transcribe them to your guitar so that the fingerings and rhythms make sense to YOU.
If you are lucky, the piece will have the fingerings on the sheet.
For example, [url=http://www.usmma.edu/parents/sheet%20music%203.gif]take a look at this sheet of music[/url].
See how the fingerings are labeled above the chord name above the notes? I know it's hard to see, sorry. But hopefully you get the idea.
It takes quite a bit of memorization regarding chord names and constructions, but hopefully you will learn quickly.
In short, it's going to take a lot of work and patience on your part. But man, jazz band is going to be a lot of fun.
Whatever effort and work you put into it, the more you will get out of it.
I deeply apologize if I misinterpreted your post, but I hope that you find this somewhat helpful. Feel free to ask questions, this was extremely, extremely bare-boned. I'm also kind of operating under the assumption that you [hopefully] know beginner logistics when it comes to music, such as notes, duration, and all that.
Sorry, but good luck
