I'm pretty new here, but I think I can answer this one....
You knit 2 stitches, then purl 2 stitches, then keep repeating this pattern across the row.
For the next row you will knit where you purled, and purl where you knitted.
In the end the piece will look like it has vertical lines....think of the cuffs on sweaters.
As for casting on....take a look at the video for the long-tail cast-on on the website here. I've tried a couple of different cast-ons before finding this site, and this one was definitely ALOT quicker to pick up and get the hang of.