Just go at your own pace though it's normal to wonder how someone else does things.
I go slow when I'm getting the parts together. I may speed piece, like the HSTs, and run them through the machine one after another but I slow down quite a bit after that. I iron every single step taking a moment to make sure that each part that goes together with another part have the seams ironed in opposite directions. I pin well, at every seam of course, and on a strip of 3" HSTs I would have a pin at each seam and in the middle of each one. That slows down the sewing to remove each pin too.
On something like this I think it is doubly important since it is not 12" blocks or something that I can square up before sewing together.