The cardigan is seamless, worked back and forth and from neck to bottom.
A video for your reference of “how to knit a perfect popcorn” has been uploaded to Instagram: jjloveknitting.

This pattern includes direction for sizes of 1-2 (2-3) 3-4 (4-5) 5-6 (6-7) 8-9 (10-11) y.

needle: 3.25/3.75mm needle
notions: 2 markers, 3 nos. of 15mm button