Okay, so I think what happens is this: You cast on two. These will end up on the left needle. Just treat them as regular stitches to bind off. So the next four you bind off will be the two you just cast on, and then the next two, which were there from before. The new cast on stitches will get bunched up between the regular bind off stitches and make your picot bumps.
There is no right way to knit; there is no wrong way to knit. So if anybody kindly tells you that what you are doing is "wrong," don't take umbrage; they mean well. Smile submissively, and listen, keeping your disagreement on an entirely mental level. They may be right, in this particular case, and even if not, they may drop off pieces of information which will come in very handy if you file them away carefully in your brain for future reference.