Hi Lilli, I saw this in the daily blog a while back - maybe you did too - but it shows how to use the binder foot.
[url]daily-blog/110-quilters-quips-tips/15768-quilters-quips-tips-bernina-in-paducah-what-is-one-of-your-favorite-accessories[/url]
As for cording, I would get that here in either a fabric shop or a haberdashery or anywhere that sells buttons and threads. I don't know what size cord you could use but I have a cording foot for my machine and I tried to use a rat-tail cord I had but the cord was too big (it was about 1/16th of an inch wide.)