Tabbing out a tune is one of the most time consuming activities that forum board members are sometimes asked to do. It is the only thing I can think of right now that doesn't ask them to just give information that they have already accrued, which they are happy to do.
Aside from tooka's advice, my suggestion would be:
1. Find as many versions as possible of the tune you want tabbed.
2. Purchase the Amazing Slowdowner, or something similar. It's an invaluable learning tool, and very easy to use. You might have to get a few bits of software to convert files to appropriate formats.
3. Slow stuff down and tab it. It's a great way to learn a piece; it even teaches you to hear unintentional mistakes in the recording.
You'll get frustrated and have fun at the same time. ---------- YouTube SlimHarpMick a.k.a. HarmonicaMick
Here are some pointers, since you say you are knew to music.
I'd start learning the melody on one hole, and then add chords later. The version of Amazing Grace I play starts on the 2 draw, then the 4 blow. If you are playing on a C harmonica that will be 2nd position, also called cross harp, the key of G. The hardest part of learning a song is finding the first note on the harmonica.
When we talk about positions on a harmonica all we are talking about is what hole you are starting on. It's not as simple as it sounds because there is this whole circle of fifths thing you'll need to learn and harp players can't count like normal people, but the beginning part you need to know is that if you are singing do re me along with the harmonica and you sing do on the first hole blow, you are in first position. If you sing do on the second hole draw you are in second position. On a C harmonica those are the major keys of C and G respectively. This is important because lots of songs start and end on 'do', so it helps you find the first note to play.
(If you look at a piano the key of C starts on the note of C and is all white keys. Each note is a half-step apart. You'll notice that when you count the number of notes, because of the way the black keys are laid out you get a different number of steps between the white keys. That pattern is what makes a key. The blues harmonica simplifies this- unless you are doing bends and overblows and such you only have the white keys. This makes it real easy to stay in key when you are starting out, but because of that pattern, unless you know how to do all the bends and overblows and stuff you can only play a couple of keys on one harmonica. The hard part of harmonica is knowing what note to start on, which segues into the next part...)
There are two first steps when you try to figure out a song. If you are playing along with someone you need to know what key you are in so you can pull out the right harmonica, and you need to know what note to start on. Finding out the key is the hard part. Different versions of the same song can be in different keys and if you are playing along in the wrong key it will sound terrible. If you are playing with other musicians you can ask, otherwise you can just go through your harps through trial and error. (There is also a neat little plug-in for Windows Media Player called the Muse-On Music Detector that will give it's best guess as to what key a song is in.) If you aren't playing along with anything it doesn't matter what key you are in. You just need to know what note to start on.
Amazing Grace starts on 'Do' so to play it in first or second position you start on either the 1 blow or the 2 draw. The pattern of notes on the harmonica will let you figure it out from there. Just think in your head, 'is the next note up or down' and work your way through it. You'll remember it better if you figure it out. Here are some useful sites. I can never remember all the scales and which key is cross harp for what so I keep these bookmarked.
