I've been playing guitar for three years now. And there's a pretty simple version of decode here:
http://www.ultimate-guitar.com/tabs/p/paramore/decode_ver4_crd.htm
It's simple chords.
Not perfect, but it should get you going.
I play in a band, and we do crushcrushcrush.
That's pretty simple too.
It's up to you what you do, but I'd say that version of decode.