How to make a ribbed hat? Help pleaz?? 10 easy points?

Ok i have some size 10 circular knitting needles and i have knitted other prjects like quilts and hand bangs. My boyfriend wants me to knit him a ribbed hat. For this hat i would like to ues size 10 circular needles and some skinny blue yarn. Also his head is 23 inches wide around. So how many sts would i have to cast on. All of the patterns ive seen online are not matching my needles or yarn. Please help!!!!