Print or trace the block diagram onto the dull side of freezer paper, and cut out the "frame" as in the photo below.
Out of main block fabric, cut a 6" x 6" square. I like to cut the fabric bigger and trim it down later because with applique there is sometimes a bit of "shrinkage".
Iron the freezer paper frame onto the right side of the fabric square.
I like the "freezer paper inside" method for melons.
Out of background fabric, cut a 6"x 6" square.
If the freezer paper frame will still stick, iron it to the right side of the background fabric square.
If not, you'll have to retrace/reprint the block.
Cut out the inside of the frame, leaving a scant 1/4" seam allowance. Clip the curves.
Baste through all layers.
Remove the freezer paper and trim away any excess main block fabric from the back of the block.