I was ready to tear my hair out yesterday while trying to figure this out.
Different day, different perspective.

I've got 4 done and working on #5. I finally GOT IT!
Now, I'm a pretty self-taught beginner crocheter and I'm using the hook sizes they say to use and my squares were just about right now - without being blocked (have never done that - I'll get around to it).
This pattern is only about 1/2" off, so I should be right on after blocking and my edges will be the same size.
So, I don't know if I'm lucking out because I don't know the "right" way to do these things, so I just go with it (today

) or what, but it's working.
I did have to stop looking at the written instructions for the first couple of pieces, but now that I figured it out, I'm using the pattern and it's working.
I've never really followed a pattern before, I just do whatever to my afghans and hope, so patterns, both written and diagrams are brand new to me.