While you might initially be confounded by the D-rings on a belt, fastening a double D-ring belt buckle is actually quite simple. Once you have fastened your D-ring belt buckle, you can simply pull the loose end of the belt to tighten it, or pull extra belt from the D-rings to loosen it, rather than having to unfasten and adjust the holes as with a traditional belt.
Thread the belt through your belt loops while wearing your trousers.
Hold the D-rings in one hand at the position you want them to be after your belt is fastened.
Pull the loose end of the belt through both D-rings.
Separate the two D-rings so there is enough space for the belt to pass between them.
Loop the loose end of the belt back to the D-rings so that it folds over itself.
Pull the loose end of the belt through the D-rings, going over the closest ring and under the second ring.
Pull the loose end of the belt until the belt is tight, but comfortable around your midsection or hips. The D-rings should be resting flat against your trousers.
Tuck the loose end of the belt through the closest belt loop on your trousers.