I used thick DK (art of knitting yarn) a 3mm hook and made a foundation chain of 25 stitches. I joined it into a circle with a slip stitch, without a twist, then tested it round my phone.
I used a stitch marker to mark the end of the round and made two rows of dc in white.
I continued in blue until it was the length of my phone and then rather lazily just dc along the bottom without turning it inside out or breaking the yarn. Sew in your ends and add the cutest button you can find in your stash.
I didn't sew it on, I tied it on by threading ribbon through my needle and tying it at the front, twice.
Big Sis sat alongside us 'ladies' learning to chain. It is amazing what you can make for your Barbie with just chain stitch.
...a belt, scarf and hair tie.
A happy time for all of us.
PS.I am experimenting with larger pictures.
Do you feel shouted at? Do let me know.