The first knot you must learn in Boy Scouts. It is very simple and is quite useful for joining two ropes together.

  1. Hold one end of each of the ropes in each hand.
  2. Place the right end over the left one , loop it under and then back up (like the beginning of tying your shoe).
  3. Take the new left side (which was the right one before step 2) and repeat step 2 placing the left over the right and looping it around it.
  4. Grab each side of the knot in each hand an pull until tight.

There, now you have a square knot.