This tutorial uses a knot known by many names; Josephine, Double Coin/Prosperity and Carrick Bend. It creates a decorative strip that can be easily finished into a bracelet or bookmark depending on your fancy.
Its takes a couple of goes before the knot makes sense and its one that while not complicated, takes patience to get right. Although you can use any cord to do this, I would recommend a minimum of 2mm the first time you try as it makes it simpler to learn.
Still with me? Ok, lets try doing another, this time starting on the right side (which creates a flatter form that doesn’t want to twist
PS, I’m using a piece of foamboard as a base, with pins to hold the top (and other parts of the knot if needed) in place, but you can use a foam macrame board, clipboard or just tape it down on your work surface.