To tie the overhand knot, make a loop and pass one end of the string through the loop and tighten by pulling both ends. To tie a double overhand knot, make a loop and pass one end of the string through the loop twice before pulling both ends to tighten the knot. To tie a surgeon's knot, take the left string and bring it over and around the right string twice. Then take the right string over and around the left string and pull both ends to tighten, leaving a complete loop of string below the knot. And finally, to tie the adjustable (or sliding) knot, take the right string and make a double knot around the left string. This will leave the left string with the ability to slide through the double knot. This knot can be used to make adjustable length necklaces and bracelets by tying the knots on both ends.