Sleeve with provisional cast on

Hello!

I am working on this sweater http://www.elann.com/ShowFreePattern.asp?Id=138024and am at the round to do the provisional cast on for the sleeves. I think I understand how to do the cast on, but confused what to do after I put the 18 stitches on a holder. It says to join a new ball of yarn and do the provisional cast on then join yarn and continue.
What I don’t understand is how do I join the yarn to do the provisional cast on and then join another ball of yarn to continue?
Completely confused!!!
Thanks

You should use a different color extra piece of yarn to do the provisional cast on. You don’t have to join this to anything, just put it on your needle. Then, to join your main yarn, just knit into the stitches that are on the needle from the provisional.

thanks Ingrid!, :muah: I knew you would have the answer. :shrug: Don’t know why they can’t write this in plain english!
Thanks again!