KF&B is an increase. You are going to knit the stitch but before you take it off the needle, you're going to knit into the back of the same stitch. So, after you've wrapped the yarn and are ready to remove it from the needle, bring the right needle around to the back of the left needle and insert the right needle into the stitch you just knitted. Wrap the yarn as you would to knit and bring the needle back under the first stitch and off the needle. http://www.knittinghelp.com/knitting...ar-english.mpg
I forgot to answer your 2nd question: K2TOG is a decrease. Instead of putting your needle in one stitch, you're going to put your needle in two stitches and knit them together.