I have my fabric, some very lightweight stabilizer, probably ten years old so who knows what it is, and your cording material. Here and on the cranberry dress I am using floss, all 6 strands. Pearl cotton works wonderfully as well and even a couple of strands of your sewing thread. Just don't use anything with lots of fibers, like yarn.
You can see my foot has a prong on either end. Cut a piece of cord a good 10 inches so you will have something to handle. While your foot is on the machine, and not in space for taking photos, wrap the center of the cord around the back prong. Pull the cord under the foot and place the cords into the slots in the other prong. Give them a tug. On my machine they will now stay in place.
This photo, against the fabric shows this step a little better. Holding your cords slightly snug and out of the way to the left, start making your buttonhole. Just let it do its thing.
Next I take my stabilizer off the back of the BH. Then I give the back a good soak of Fray Bloc. Off to the ironing board where I iron it dry till the Fray Bloc is all dry. It only takes a few seconds. Now it is ready to clip. I highly recommend a buttonhole chisel and board if you don't have one. You will wonder how you did without it.
Always make sure you do test buttonholes to try the fit. Adding the stabilizer, Fray Bloc, and cord will definitely tighten up the hole. Make sure your samples have all the parts before you decide how big it should be. This is really one of those tiny details, machine details, certainly not couture. But it is quick, easy, and gives a niced finish than just the basic machine BH. Here you can compare the differences.
Each sample has a corded BH and a regular machine buttonhole. The cord really fills in and smooths the stitching out. Hope you give this a try and definitely go check your manual as all machines are a bit different. I don't see why you can't place a pin about a half inch above the BH and wrap the cord around the pin and just hold it straight under the foot. Did Nancy Zieman do that once on her show? .....Bunny