Fingerless gloves

I am doing fingerless gloves and my pattern tells me to bind of 18 stitches for thumb and continue pattern to end or round. Then cast on 6 sts using cable cast on.

My question is this: if my yarn in at my last stitch on right needle, how do I start the cable cast on of 6?

Whether you are using DPNs or whatever, turn your work so that the needle with the yarn hanging from it is in your left hand then use a handy needle to cast on 6 using a cable or other knitted on cast-on. See the cast-on videos if you don’t know this cast-on. Then turn back to keep going the way you have been going.