Piba-cardigan is worked seamlessly from top down.
When choosing size do not rely solely on age categories. Choose size based on the actual chest measurement noting that approximately 5 cm/ 2 inches of positive ease is already incorporated into the pattern.
Note that the body and sleeve lengths are given in pattern after blocking so make a swatch to see how the fabric behaves after blocking and adjust body and sleeve length accordingly.

Sizes

0-3, 6-9, 12-18 months, 2, 3-4 years

Finished measurements after blocking

Chest circumference (buttoned) 49 (54, 59, 62, 65) cm/ 19.25 (21.25, 23.25, 24.5, 25.5) inches.
Pattern has detailed schematics.

Yarn

Cascade Yarns 220 Superwash (100% wool) 201 m/ 220 yds per 100 g or any Dk or worsted weight yarn which knits to gauge. The sample cardigan was knitted with colourway 1926 Doeskin Heather.

Short sleeves:
225 (315, 420, 460, 525) m/ 246 (345, 460, 503, 574) yds

Long sleeves:
250 (315, 420, 525, 630) m/ 273.5 (345, 459, 574, 689) yds

Needles & notions

3.75 mm/ US 5 and 4.5 mm/ US 7 (80 cm/ 32 inches or longer for magic loop) circular needle or set of DPNs or size to meet the gauge
scrap yarn or stitch holders
markers, tapestry needle for weaving in ends
5 (5, 7, 7, 9) buttons, approximately 1.5 cm/ 5/8 inches in diameter

Gauge

22 sts x 32 rows = 10 x 10 cm/ 4 x 4 inches with larger needles in pattern after blocking