How to Tie a Bowline Knot
The classic climber's waist loop knot for ultralight, and the strongest single-line knot you can tie in cord.
Bring the free-end around your waist in belt fashion.
Lay your free-end hand atop the standing cordage, palm down.
Take the free end and run it upwards through the loop ...
... around the standing end, and back down through the loop in exact reverse. "The rabbit climbs out of its hole, around the tree, and back down into the hole."
Look closely at the sample knot and how the loop is made. When tied incorrectly, the bowline turns into a slip knot.
Bowlines are strong, but not that secure, for critical uses they should be backtied with a half hitch or other secure knot.
For climbing use, snug up the waist loop until it's belt tight around the narrowest part of your body, and backtie it.