The main thing with that groove he is playing is the accents on beats 2 and 4. That just means they are played "louder" than the rest of the strums. You could use a really simple pattern such as:
/ ↓↑ ↓↑ ↓↑ ↓↑ / which is a simple down/up strumming pattern repeated 4 times (one for each beat in the bar). Translated to beats it would be / 1+ 2+ 3+ 4+ / with each strum being spaced evenly in time. The key here is to accent the 2 and the 4 (both ↓ strums) a little more loudly than the other beats. This gives the same sort of drive that a snare drum on those beats in a drum groove would have. The accents kind of push the groove forward and give it a dynamic.
In that video he is sometimes (interjected occasionally) adding an "anticipated" accent that happens on the upbeat before beat 4 as well. I would work out the simple version with just 2 and 4 accents and then add the anticipation. The difference would be this:
/ ↓↑ x↑ ↓↑ x↑ / (the x's are the accents on 2 and 4)
/ ↓↑ x↑ ↓x x↑/ (here the ↑ beat on the + of beat 3 is accented "anticipating" beat 4, which is also accented)
/ 1+ 2+ 3+ 4+ / (here are the numbered beats)
Try listening to the video and finding the accented (louder) beats and then trying to assign those a number (2 and 4) and count along with his playing. This should hopefully orient you somewhat as far as matching up the written out pattern with the music as it plays. I hope this makes some sense, this is much easier to demonstrate than write about for me!