That's an easy carpet to seam. The only thing I do different than that guy in the video is I am always on the carpet with the selvedge side to my right side with the blade on the seam side as opposed to the selvedge edge side.
Probably doesn't make a difference but I'm stuck in my ways.
I'm going to read that back to myself a few times.... I think I get it, but it's 12:03am.