When I have these rows of blocks laid out the way I want them (usually on my bed), I pin numbers on the first block in each row. Then I turn down the second block of row one and put a pin where I will begin to sew that seam. Flip that back up and turn down number three. Pin that and flip it up, etc. I can get the whole thing pinned and to the sewing machine, and I can sew it whenever. Everything is numbered and pinned. When all rows are sewn, sew the rows together.
Have fun!