I had to write the pattern out so that I could follow it better (see below). The matching hat is something I designed to go along with the sweater.

I was confused by where/how to cast on the stitches for the underarm… so I researched other sweaters & made adjustments accordingly to the pattern. I learned to work it differently than how the pattern describes (see below).

Also the pattern gave no measurements… again I did some research to find out baby sizes.
Size 3 mo
Chest: 16 inches
Sleeve length: 6 inches
Back to waist: 6 inches

Size 6 mo
Chest: 17 inches
Sleeve length: 6.5 inches
Back to waist: 7 inches

Size 12 mo
Chest: 18 inches
Sleeve length: 7 inches
Back to waist: 7.5 inches

Size 18 mo
Chest: 19 inches
Sleeve length: 8 inches
Back to waist: 8 inches

I made the smaller size, so these directions only incorporate changes for the smaller size. They are typed up as best I as I remember. The way I knit, this will fit a 3-6mo.

C/O 60
Row 1-2: K

Row 3: (rs): buttonhole row
BOY Version: K 2, y/o, K 2 tog (boy); work to end
GIRL Version: K across to last 4 sts, K 1 y/o, K 2 tog, K 1

Row 4-5: K
Row 6 :(ws) K 4, P across to within 4 sts of end, K 4
Row 7: K
Row 8: K 4, P across to within 4 sts of end, K 4
Row 9: K 4, (increase in next st, K 2) Repeat across, end K 4 (78 sts)

Row 10: (ws) K 6, slip 2 as if to P, with yarn held in back of work, K 2, slip 2 repeating across, ending with K 6.
Row 11: K

Row 12: (ws) K 6, slip 2 as if to P, with yarn held in back of work, (K 2, slip 2) across, ending with K 6.
Row 13: K 4, (increase in next st, K 3) repeat across, end K 5 (96 sts)
Row 14: K 4, P across to within 4 sts of end, K 4
Row 15: K
Row 16: K 4, P across to within 4 sts of end, K 4
Row 17: K 5, (increase in next st, K 4) repeat across, end K 5 (114 sts)

Row 18: (ws) K 6, slip 2 as if to P, with yarn held in back of work, (K 2, slip 2) across, ending with K 6.
Row 19: K
Row 20: (ws) K 6, slip 2 as if to P, with yarn held in back of work, (K 2, slip 2) across, ending with K 6.

Row 21: K 6, (increase in next st., K 5) across, end K 5 (132 sts)
Row 22: K 4, P across to within 4 sts of end, K 4

Row 23: (rs): buttonhole row
BOY Version: K 2, y/o, K 2 tog (boy); work to end
GIRL Version: K across to last 4 sts, K 1 y/o, K 2 tog, K 1

Row 24: K 4, P across to within 4 Sts of end, K 4
Row 25: (K 6, inc. in next st) across, K 6 (150 sts)

Row 26: K 6, slip 2 as if to P, with yarn held in back of work, (K 2, slip 2) across, ending with K 6.
Row 27: K
Row 28: K 6, slip 2 as if to P, with yarn held in back of work, (K 2, slip 2) across, ending with K 6.
Row 29: K
Row 30: K4, P across, K4
Row 31: K

Row 31: (ws) PLACE MARKERS – Work 26 (30) sts, PM, work 26 (27) sts, PM, work 46 (54) sts, PM, work 26 (27) sts., PM, work last 26 (30) sts. (150) (168) sts. total

Row 32: Increase Row: (K to within 2 sts. of marker, increase in next st, K1, pass marker, increase in next s) repeat 3 times. (158) (176) sts.

Row 33: K4, P across, K4

Rows 34-41: Repeat rows 31 & 32 four times

Row 42: (rs) Work to within 2sts of marker, increase in next st, k1, remove marker, Put sleeve stitches on a holder, c/o 4 sts under arm, remove marker, increase in next st , work across the back to within 2sts of next marker, increase in next st, k1, remove marker, put sleeve stitches on a holder, c/o 4 sts under arm, remove marker, increase in next st . K to end

Row 43: K4, P across, K4
Row 44: (rs): buttonhole row
BOY Version: K 2, y/o, K 2 tog (boy); work to end
GIRL Version: K across to last 4 sts, K 1 y/o, K 2 tog, K 1
Row 45: K 4, P across to within 4 sts of end, K 4

Row 46: K
Row 47: K 4, P across to within 4 sts of end, K 4
Rows 48-63 : Repeat rows 46 & 47

Row 64: (rs): buttonhole row
BOY Version: K 2, y/o, K 2 tog (boy); work to end
GIRL Version: K across to last 4 sts, K 1 y/o, K 2 tog, K 1
Row 65: K 4, P across to within 4 sts of end, K 4

Row 66: K
Row 67: K 4, P across to within 4 sts of end, K 4
Rows 68-74 : Repeat rows 46 & 47

Row 75-78: Decorative row: repeat rows 10-11 twice

Row 79: K 4, P across to within 4 sts of end, K 4
Row 80: K
Row 81: K 4, P across to within 4 sts of end, K 4

Row 82-83: K
Row 84:(rs): buttonhole row
BOY Version: K 2, y/o, K 2 tog (boy); work to end
GIRL Version: K across to last 4 sts, K 1 y/o, K 2 tog, K 1
Row 85-86: K
BO on wrong side in K

Sleeves:
Pick up 34 stitches of one sleeve plus 6 sts. from underarms (40 sts.).
Work in stocking knit for 5 inches
Row 1: Decrease row: (k8, k2tog) around (36 stitches)
Row 2: P2, sl2, with yarn in front
Row 3: K
Row 4: P2, sl2, with yarn in front
Row 5: K
Row 6: K
Row 7: (k7, k2tog) around (32 stitches)
Row 8: P
Row 9: K
Row 10: P
Row 11: K
BO on right side in purl