You are going to put your needle in the stitch, as if you are about to knit with it, but instead, just slip the stitch off the left needle onto the right needle. Then knit the next stitch normally. This give the edge a nicer appearance.
PSSO means to pass the slipped stitch OVER the other stitches. Here is a page that show many decrease technique. If you go down to SKP and watch the video, it shows how to PSSO.
Okay K1B, means to knit into the stitch that is below the next stitch. Locate the knit "v" below the next stitch, and knit into it as it if the next stitch on your needles, but before sliding it off, knit into the back of it as well. This means, with the loop on your right needle, go around the side and knit into the other leg of the stitch, then slide both off onto the right needle.