This pattern is designed as photo prop.
Romper is knitted bottoms up, mainly in rounds on double pointed needles as one piece as much as possible (to avoid sewing pieces together).
Size: newborn (up to 1 month old baby)

Materials used:
Yarn: worsted weight, I have used Himalaya Everyday 250m/100g
Needles: 7US, 4.5mm – selection of DPNs & circular 18” and 32”
Tapestry needle
Crochet hook 4.5mm
Button 13mm – 2 pcs