Okay, say you're holding your needle in your left hand with all the stitches on it and for example the pattern says to slip 25 stitches onto stitch holder. You can use actual stitch holders, which look like gigantic safety pins, or you can just use a scrap of yarn. Basically all you will do is hold the stitch holder in your right hand, almost as though it were a knitting needle, and pass the stitches one at a time from your working needle onto the stitch holder. You will pass them over just as they are - no twisting or knitting or purling - just move it off your needle and onto the holder. Does this help??? If you are using a scrap of yarn, what I do is thread it into a tapestry needle, then pass the stitches one at a time off the working needle, onto the tapestry needle and thus onto the piece of yarn, which works just as well as a stitch holder as anything!!
Hope that was a bit helpful and not too longwinded!!!