This square has been a particular challenge because I am not at all certain how it will fit into the blanket as a whole. Additionally, there is no good closeup photo available, and I am at best, guessing as to how the border has been done.
The first noticeable error in the written directions comes in Round 5 which directs the crocheter to work the round in double crochet, when it is clear from the picture provided that the final round is worked in single crochet.
I did as follows:
Rnd 5: With a new color work 1sc in each st along each and and (1sc, ch2, 1sc) in each corner all the way around. Join with sl st to first sc made and finish off.
The resulting square looks like this:

Not discussed at all in the directions is the border that goes for what could be called the final 3/4ths round.
On one side I did this:
With right side facing 3dc into the ch-2 corner space, *(skip 2sc, and made 3dc in the next dc), repeat from *four times more, 3dc in next ch-2 corner space, finish off.
Working along the side opposite the one just worked and with right side facing, make 1sc in the ch-2 corner space. sc in each of the next 14sc, (sc, ch2, sc) in next ch-2 sp, sc in each of the next 14sc, sc in next ch-2 corner space. Finish off.
The completed square looked like this:

I will have a better sense of how this has actually worked out when I complete Squares D-3 and C-3 and find out how E-4 fits with these other pieces.