Doll Sweater Question

I’m making this American Girl doll cardigan and I’m working on the back right now and I’m confused by these directions.

To shape neck, K13, place next 8 stitches on a holder after knitting them, K to end. Working each side seperately, at the next neck edge, bind off 3 stitches. Decrease 1 stitch each row three times (I like to work my decreases one stitch in from the edge). Work until piece is 6 inches from beginning and put remaining 7 stitches on a holder. Reverse shaping to work the other side.

I did the k13, place 8 sts on holder, k to end. My question is I don’t know where I’m supposed to bind off the 3 stitches. At the beginning of the row? or right next to the stitch holder? And if it says decrease 1 stitch each row 3 times, does that mean I do 3 rows? I’m just really confused by this whole part in the directions because I’ve never made a sweater like this before, just really simple beanie baby sweaters.

Purl back across where your yarn is and turn when you get to the st holder. BO 3 to start the knit row, knit to the end. Turn again and purl across to the holder, dec when you get there, turn and dec at the start of the knit row. Dec at the end of the next purl row, then keep going for 6 inches.

What Sue said will work. Then begin with a purl side row on the other side and do the same thing making your decreases at the beginning of the purl side rows.

On the other side, you’ll start with the BO on the purl row, but you do the decs at the neck edge on both purl and knit rows.

Thanks! It makes sense now and I tried it and it worked.