Using a waist trimmer belt is pretty easy.
When you buy it, you will find it inside a box, packed and rolled. You just need to unroll it and stretched out.
Just hold both ends of the belt. The darker side should be on your back. You can wear a thin spandex t-shirt and wrap the belt around the abdominal area.
Make sure that the belt is covering the front side of the abdomen. Just wrap the end of the fastening belt around the torso making sure that you are comfortable wearing the waist trimmer belt and fully secure.