micheals or any arts and crafts store
you can go to this site, its awesome it shows you how to make all kinds of stuff:www.boondoggleman.com
From a lanyard string shop
A three-string lanyards starts with a regular knot. Here you can find a video on how to do it: http://www.laneyards.com/2008/10/triangle-3-strand-stitch.html
This site shows hot to start a six string lanyard: http://www.laneyards.com/2008/10/brick-supersquare-stitch.html