How To Read Tablature 

Tab (short for tablature) is a quick way to sight read the guitar fingerboard.
Here's a quick 101 on how to read it.

-----------------The Tab Lines ---------------

There are 6 lines representing 6 strings on the guitar.

Looking at a right hand guitar as if you were holding it.
The top line (1st String) is the skinniest string on the guitar.

E:--------------  >>> 1st string
B:--------------  >>> 2nd string
G:--------------  >>> 3rd string

D:--------------  >>> 4th string
A:--------------  >>> 5th string
E:--------------  >>> 6th string

The bottom line (6th String) is the fattest string on the guitar.

This layout is used for all stringed instruments: Mandolin, Banjo, Bass, etc...

So here's the guitar layout:

E:-----1st string---- >>> Skinniest...highest sounding
B:-----2nd string----
G:-----3rd string----
D:-----4th string----
A:-----5th string----
E:-----6th string---- >>> Fattest...lowest sounding

----------Reading The Numbers On The Lines ---------

The numbers in or on the tab lines represent the frets where you will place your left hand fingers.

Example: 2 means the second fret. So you would press down the string just to the left of the 2nd fret bar. (See Fig.1) 

A 0 (zero) would mean that you play that string open (not touching the string with your left hand).

3 means the third fret. So you would press down the string just to the left of the 3rd fret bar.

      2nd fret    open string
         ..|           .. |
E:-------2------------0---------- >>>1st String
B:-------------------------------
G:-------------3----------------- >>>3rd String
D:-------------------------------
A:-------------------------------
E:------------------------------- >>>6th String

-----------How It's Played ----------

Tablature is read from left to right. Play the notes in the order that you see them.

Here is how you would play the exercise below:

first you play the 5th string...3rd fret

then the 4th string...5th fret

then 4th string...3rd fret

then 3rd string...5th fret

then 4th string...7th fret

E:----------------------- -->1st string
B:-----------------------
G:--------------5--------
D:--------5--3-----7-----
A:-----3-----------------
E:----------------------- -->6th string

Hope this quick 101 will jump start you on your way to reading Tablature.