Step 1: The weaving disc.
All you need to weave your cord is a roughly-circular piece of card a couple of inches across.
Poke a hole in the middle, about quarter of an inch across (pencil-width is fine), and cut eight slots evenly around the edge of the card.
You may also find it easier to manipulate the cord in you cut a tiny V-shaped notch at the end of each slot.
It doesn't have to be an exact size, or an exact shape, so you can knock one together from any scrap card you have lying around.