The buckle has a tooth that catches on the track in the leather.
There is a lever on the side of the Buckle that when you press it will lift the tooth out of the track.
If the belt is very tight around the waist, and the pressing of the lever on the side of the Buckle isn’t releasing the tooth from the track, then push the leather further into the buckle as you are pressing the lever, then pull out to release and this will take the pressure off the track and the tooth and assist in releasing the leather from the buckle.
*If you wrap the belt around you with the buckle in your right hand lever will be present on the top.
For ease of use;
Use your right thumb to press the lever.
Use your left hand to push the leather out of the Buckle.
*If you wrap the belt around you with the buckle in your left hand the lever will be present on the underside.
Use your left index finger to press the lever.
Use your right hand to push the leather through out of the Buckle.