Cast on 56 sts using a long tail cast on (or your favourite stretchy alternative)
Join to knit in the round being careful not to twist and place a marker to indicate the start of the round.
Work 6 rounds K1,P1 rib
Work 18 rounds pattern
Rnd 1: K2,P1 (K3,P1) x 13, K1
Rnd 2: (K1,P3) x 14
Rnd 1: K2,P1 (K3tog,P1,K3,P1) rep to last 5 sts, K3tog, P1,K1
Rnd 2: (K1,P2) to end
Rnd 3: K2, (P1,K5) to last 4 sts P1,K3
Rnd 4: as 2nd row
Rnd 5: K2tog, (P1,K1,P1, K3tog) rep to last 4sts, P1,K1,P2tog
Rnd 6: (K1,P1) to end
Rnd 7: (K1,P1) to end
Rnd 8: (K1,P1) to end
Rnd 9: K2tog to end = 14sts
Cut yarn and thread through remaining sts, pull up tight and weave in ends.
If you want to use a thinner yarn, just choose the appropriate needle size and cast on more sts and knit more rounds until it looks right.
Though the main body pattern works in multiples of 4, for the decreases you need multiples of 8 (or you'll end up having to fudge it to get it to work properly) so ideally cast on 56, 64, 72 or even 80.
I have also combined more strands of a thinner yarn to get something that feels chunky, and that has worked well too.
As with all my patterns you are welcome to use them as you wish (apart from reproducing and claiming them as your own) but if you could make a hat and donate it to charity that would be great.
If you'd like to see some of the variations I've made, including a scrappy hat from a magic ball made with oddments from another charity project, then pop over to Ravelry and have a look at my projects.