Casting on in the middle of a row

I am thrilled to find this sight! I am a relatively new knitter and I can use as much help as I can find.
I am beginning baby sweater, and I have knitted the first 20 rows. The pattern instructs me to k7, slip11sts onto a stitch holder. I have done that. next it tells me to cast on 11sts for pocket lining, 11. My question is "Do I cast onto the right needle? How to I go about doing that?:

thank you

You can use the knitted or cable cast on. Place your right needle in your left hand as if you were at the end of a row. Knit into the first stitch, but don’t slip it off and place the new stitch at the end of the left needle. Do 10 more, then turn the needle and put it in your right hand and knit the rest of the stitches on the other needle.