[d] enclosed in brackets

Judy's Magic Cast-On seems to elude me.

It's not that I don't get it, it's just that I can't seem to get it to work the way I think it should. I searched for videos on it, and it's tough because I'm using DPNs instead of circular needles. The video below is the closest, but I still feel like I'm missing something.

Once I've done a few of the rows, I feel like it should be pulling together with the increases, but it still looks flat to me. Anyone care to offer advice?