I’m not a huge YouTube fan (most posters waffle for ages and eventually tell you something they could have condensed into a few lines of text) but in this case, the video is more informative than the picture + text version.
I found that I had clearance issues — I think I’m using older model backing plates with my new-model gearbox. A trial assembly showed that I needed to remove some metal from the bearing cover to allow it to seat flush on the brake backing plate.