I hope this makes sense. I drafted out for you.
center square is cut 6 7/8"
inner triangles cut 2 5" sq and cut once diagonally
corner squares are cut 5"
flying geese rectangles cut 4 at 5" x 9 1/2"
cut 8 5" squares, draw one diagonal line and sew on that line, cut 1/4" away and press to outside, repeat for other side. In pic, one done in red, one done in green.
I have corrected the 5" x 10" rectangle.