This cardigan and shorts set has clear line by line instructions.
The size depends on the yarn and needle sizes used as listed below

Materials
21-22” Doll / 0-3m Baby
3.25mm needles (smaller)
4mm needles (Larger)
200grms Double knit Wool

19-20” Doll/New-born baby
3mm needles (smaller)
3.75mm needles (Larger)
150grms Double knit Wool

16-18” Doll / Small New-born
2.75mm needles (Smaller)
3.25mm needles (Larger)
120grms 4-ply wool