HOW TO CROCHET A SWEATER /climbing shells stitch. Pattern Tutorial/DIY #crochetsweater

I am using yarn Seagull,100 percent Acrylic. I am doubling it because its Dk size. on working on the back piece, chain 34 rows-S, 38-40rows=M, 45-48rows =L. ARM chain 16 S, 18-20 M, 25 L Ribbing chain 35 S, 40 M, 45 L