I working on these mittens, and the pattern says, “Using waste yarn, k7; slip these sts back to left needle and k them again using working yarn; work in 4x1 Rib as set to end.” (http://knitty.com/ISSUEsummer06/PATTfetching.html)
Even though I’ve never personally done this, what you’re doing is called provisional cast on. These 7 stitches will later be taken out (the 7 stitches with the waste yarn) and you’ll be working with your actual yarn. You’ll just need to be very careful as you rip these stitches out, doing it slowly, one stitch at a time, and the loops you’ll pick up will be your “live” stitches. Just take a scrap piece of yard, cast on 7 stitches and cut the yarn, then slip them back onto your left needle and pick up your working yarn and begin knitting. Is this clear as mud??:p:p
It’s not exactly a provisional caston. Just do exactly what it says. Pick up some spare wool knit the next 7 stitches with it (drop the main wool), slip the stitches back to the LN, knit them with main wool, continue in the rib. What part exactly are you having trouble with?
And check out the KALs here and on Craftster for answers to other questions if you get stuck too - lots of pics and good explanations.