Pattern has instructions for a one-piece romper with pompom hat.
You will need 5 buttons for the romper.

Finished measurements:
Chest circumference: 18( 19.75, 20.5, 21.25, 21.75, 22.5)“ 46( 48, 50, 52, 54, 55, 7) cm
Finished length: 20.5( 21.75, 22.75, 24, 25.5, 27.5)” 52( 66, 58, 61, 65, 70) cm
Sleeve length: 6 (6.25, 6.5, 7.5, 8.25, 9.5)“ 15( 16, 17, 19, 21, 24) cm
Hat circumference: 13.5( 13.75, 14, 14.5, 15, 15.75)” 34( 35, 36, 37, 38, 40) cm

Yarn used:
Sirdar Snuggly DK
Romper
A. 487 Cloud - 1 ball for all sizes
B. 187 Precious - 1( 1, 2, 2, 2) balls
C. 326 Denim Blue - 2(2, 2, 3, 3, 3) balls

Hat
A. 487 Cloud - 1 ball for all sizes
B. 187 Precious - 1 ball for all sizes
C. 326 Denim Blue - 1 ball for all sizes