The video tutorial describes how to tie your belt (obi or sash) around your gi suit for aikido. This method is particularly good for aikido as the finished knot is fairly flat and the layers of the belt do not cross at the back.
Step 1 - Start with the logo end of the belt hanging down your right leg (logo facing out) holding it at the right hip with the right hand.
Step 2 - Wrap the belt across your front wrap it around your waist twice, ensuring that both layers of the belt sit on top of one another.
Step 3 - Try to get the loose ends roughly the same length at this point. This will make it easier to keep the ends the same length when you finish.
Step 4 - Take the left-hand end (that's dangling down your left leg) and tuck it up behind both layers of the wrapped belt, passing it between your stomach and the belt. Hold this end under your chin, clamping it between your chin and your chest.
Step 5 - Bring the right-hand end (the end with the logo that's still dangling down your right leg) up and fold it over & down passing between the 2 layers of belt – don't pull it too tight as you need to leave a loop for the next step. It will now be dangling down your left leg.
Step 6 - Take the 'upright' end that's clamped under your chin and fold this back through the loop you just created & between the 2 layers of belt.
Step 7 - Flatten out the knot and pull both loose ends to tight the knot, ensuring that both ends are the same length as you tighten.