This is an awesome little picking riff to add to your repertoire. It's fun and it's pretty simple because you're mostly holding chords the whole time.
You'll need to use four basic chords: G, D, Em, and C.
Here is the pattern (the numbers represent which string to pick):
G chord: Strum, 1, 2 2, 3 3, 1 1
D chord: Strum, 1, 2 2, 3
Em chord: Strum (top 3 strings only), 2, 2, 2, 2
Pick: 2nd string second fret
Pick: 2nd string open
D chord: Strum, 2 2
C chord: Strum
Pick: 1st string second fret
Pick: 1st string open
G chord: 2, Strum
Be sure to watch the video to see how it's done. (BTW, if you'd like me to do a tutorial on how to play the whole song, leave a comment in the video!)