Cords (size of your choice) Linhasita threads, waxed threads...
 connectors, natural beads...
 a lighter, a thread burner

To start, cut a thread about 50cm to be comfortable. Once the technique is mastered, you can adjust the size more precisely.

Make a simple knot in the center of the cord, then thread the bead. Make a second knot on the other side of the bead to lock it. To make the knot right at the edge of the bead, use a needle passed through the knot, it will allow you to slide the knot as close as possible to the bead. Tighten then remove the needle.

The knot:

Place the cords in the shape of the bracelet, the 2 ends cross. If you wish, you can insert a bead on the 2 cords to help the crossing.

Put on the bracelet to determine the size and approximate placement of the knots. 

Follow the diagram above to guide you.

Pass the left cord under the right cord, then bring the left cord to form a loop. Hold it with your right hand.

Then wrap the cord around the 2 cords for 2/3 turns. You can tighten the turns, no need to keep them loose.

Finally, pass the cord underneath to enter the starting loop.

Tighten the knot gently. Then cut the cord 2mm from the knot and burn the end carefully without touching the knot. The end will melt, press with your finger to stick the tip to the knot. This will prevent the knot from coming undone. If you wish, you can also place a small drop of glue on the knot.

When you tighten the knot it will move, the challenge is to make it in the right place. To do this, plan to start it before the predefined area, because when tightening the knot it will move further. Practice on a test cord before making your bracelet.

For the second knot, proceed in the same way with the other cord. 

And there you go! Beautiful creation!