Tube Scarf for a 2-Year-Old Boy

Could one of you please help me? I’d like to knit a tube scarf for this 2-year-old boy
. How many stitches do I need to cast on, and how many rows
should I knit? Does it look better if I use a stitch pattern, or just knit stitches on one row and purl stitches on the next? Does it make sense to add a ribbed edge? Thank you so much in advance.

@gabriela-anneser
Welcome to our forum and to the portal. I’m bumping your thread again so the authors/professionals can write down a few more tips for you. Good luck.
@all
Please write down a few more tips if you have the time.