The best way to learn this song is break it down into individual riffs. There are only about 6 main riffs to learn, so with some application you'll know the entire song relatively quickly. Remember, go slow and get it right before building speed.

Intro Riff - You can use alternate down / up pick strokes if you wish - it doesn't really matter. Mute the surrounding strings with your thumb / fingers if it makes things easier.

Verse Riff 1 - This repeats a few times, but notice that different fingers are used to play it first time compared to the rest. That's down to positional play.

Verse Riff 2 - The start of the riff is the same as previously, but the tail end is different.

Repeat through Verse Riffs 1 and 2 again then:

Pre-Chorus - Short and very easy.

Chorus - Do the fast chord changes whilst strumming the open E and A strings (Thumb mute the low E if it helps). The chords are E5 and A major.

After that just repeat everything over again (including the intro riff twice).

Funky Outro - Played similar to the Chorus, but this time the chords are: G5 *3 E5 - A major - G major. Switch chords as you pick the Low E, and don't forget the funky muted strikes in between!