First of all, you need to understand that wearing a proper kit or uniform for martial art is the basic need for anyone before doing practice. You should also learn to wear a proper martial arts dress before taking your first physical lesson.
You should choose a belt that is according to your size and place it around your waist. Make sure you the belt is just above your hips on your back. Hold both ends of your belt to adjust it as from backside and front side as well.
You need to make the belt tightened from all sides because it will hold your dressing in a perfect way otherwise it will become difficult for you to concentrate on martial arts practice if your belt becomes loosened.
Now you should hold the left end of your martial arts belt and make it a little longer that the other end of the belt from your front side. After that wrap the longer end of the belt over the shorter end ensuring that longer side of the belt goes around your waist and comes in front of your again.
Make sure that the longer side of the martial arts belt will always come over the shorter side of the belt and it should also be on your right side.
Then you should hold the longer side and tuck it under both wraps of your martial arts belt and pull it out from the upper side of the belt and then fold it downside.
After that hold the shorter end of your martial arts belt and move under the longer end from left towards right side. Now you should bring this end of the martial arts belt over the top of the other end and it will make a knot through the loop.