/cgl/ - Cosplay & EGL

Could someone help me figure out this skirt from Otome no Sewing volume 3? The waistband is on a pattern sheet but the skirt part is just a rectangle that I need to draft myself. There's a ruffled and a pleated option. The blue/top number is for size S, red/middle/bold is for M and green/bottom is for L.

I don't really understand the top two pictures. What I get from it is the width of the pleats, the length of the skirts and I guess 1/4th of the width of the ruffled skirt (for M it's 45+30 = 75cm, right?). Is there anything else I'm supposed to be getting from this?
I also can't figure out how wide the skirt portion for the pleated skirt should be. Should I just add up all the numbers for my size, multiply by four and add seam allowance?