what does BO 3 sts each side 1x, 2 st 2x, and 1 stitch 3x mean
Welcome to KH!
You’re going to bind off sts in steps. Bind off 3sts work to the end of the row, turn and bind off 3 sts at the beginning of the row then work to the end of row. Repeat this by decreasing 2sts at the beginning of the next 2 rows, then repeating. Finally, bind off 1 stitch at the beginning of the next 6 rows.