This knot comes from the family of flat knots (so-called because they are flat, one-dimensional knots, who would have believed it!). Most Chinese knots are flat knots. many of them can be created using both one or two strands. This is the case with this knot.

Starting from the bottom, form a loop using the strand represented by two thin lines. The end of this strand goes towards the top.

Look at the strand represented by the single thick black line: position it in the way that the first strand would appear if viewed in a mirror. Start off from the top and position the strand as indicated.

This piece of knotting can be done with one strand. If using one strand, make sure you leave enough thread/cord after your first knotting movement to go right around your neck. Next, as indicated by the dotted line, finish the knot with this same strand replacing the second strand.
It's better to use a fairly stiff thread that will keep its shape well - and therefore the shape of the design too.