The pattern is for both an adult size using CYA 6 (super bulky) or a child’s size using CYA 5 (bulky). Child’s mitts take a size 10US/6mm dpns or circs. The pattern is very forgiving on sizes.
You will need at least one stitch marker and (preferably) one stitch holder (or waste yarn).
Please email any errata to Heather@crafting-a-life.com. I’ll get it up here asap.