Study the chord boxes. All chords that appear in a song are illustrated in a chord box, above the tablature notation. The box represents the fretboard. It has six vertical lines and as many horizontal lines as there are frets covered by the chord. For space reasons, the chord boxes only appear at the top of a tablature page and are referred to thereafter by the chord name.
Learn the symbols. As well as note order, tabs tell you how to play certain notes. For example, an "H" above a curved line between two notes denotes a hammer-on. This is a technique where you press your finger down hard on a string without plucking or picking. The pressure of the finger "hammering" onto the string is enough for the note to sound.
Practice each chord. Chord boxes illustrate the string and fret each note in the chord is located on and the finger that you should use to make the note. Fingers are referred to numerically, with your index finger being "1" and your little finger being "4." In the rare case that your thumb is required, it is illustrated with a "T." By practicing each chord shape, especially unfamiliar ones, you can play them more easily when you are working your way through the tab.
Transfer the notes from the tablature to your guitar fretboard. For example, a number 4 on the highest line of the tab corresponds to fret four on your highest string, your top E. This note is G sharp.
Play the first line of tablature. Break it down into bars, transferring each note from the tablature onto your guitar fretboard. Repeat the first bar until you can play every note correctly and confidently. Then learn the second bar. Once you have nailed the second bar, practice the first and second bar together. Pay special attention to the notes at the bottom of the tab, including guidance pertaining to guitar sound.