The video doesn’t exactly match the pattern instructions. Video says to ch2 in WS corner (pattern says ch1). Also excludes the standing dc when changing colours.
On rounds where I was not changing colours I used (ch2, dc, ch1, 2dc) in right side beginning corners, and (ch3, dc) in wrong side beginning corners.
I used a ch1 in all corners.
I ended after a rnd 5 (right side rnd). Didn’t add any border. I don’t think it needs it.