As you probably know from the Rhythm guitar part for this song, the lead is also very easy. Stick to the Drop D tuning.

Drop D: Low D:A:D:G:B:E

If you are currently in standard tuning, just play the middle D string and downtune the Low E until it matches.

For the majority of the song, both guitars do the same thing. The lead occasionally switches to play some simple melodies over the top of the Rhythm guitar chords. We'll assume you already know about the Rhythm guitar parts (including the fast bit), and just look at the melodies here.

Melodies:

Melody 1 - Do a pickslide (drag the edge of your pick along the strings) then play the simple melody. Repeat.

Melody 2 - Very similar to Melody 1. Followed by a gap (for guitars / drums).

Melody 3 - This melody is a bit different, and the closest thing to a solo in the song. After the little bend etc, switch straight into the next melody....

Melody 4 - Similar to Melody 1 (again). Repeat to the end of song.

Really there are only two main melodies to learn. Melody 1 and Melody 3. Notice that Melody 1 is played a lot, albeit with slight variations and that only Melody 3 is significantly different.

If you already know the rhythm guitar part, then learning this lead won't be much of an extra effort to complete the song!