Easy, easy, easy. The sections on this block felt positively ginormous after all the teensy pieces we've been dealing with. (By the way: "ginormous" is actually a real word now.)
25 minutes from start to finish.
Trace or print the block diagram onto your foundation paper, number as follows and cut apart as shown.
Foundation piece the two sections. Trim the seam allowances to ¼".
Attach to each other.
How simple was that?