GVWR is the max weight at which your brakes, steering and suspension are rated to perform.
Payload is the suggested number for stuff you can add to, load in...including passengers.
Curb weight is your empty vehicle with full fluids...so a full tank of gas.
To easily find your curb weight...take you GVWR minus your payload.
Using the door stickers if your vehicle ia new enough
For instance my HeftyDuty has a GVWR of 10000lbs. A payload of 2998
So my curb weight is 7002 lbs.
There so a bit of capacity over GVWR...check your axle ratings...mine is 5500 front and 6000 rear. But you also must remember some of that capacity is for inertia...weight transfers to the rear when pulling out and to the front when stopping.
The important thing is to make sure when you load you do not remove too much weight from the front. This is why a truck has a rake to it...and why I do not like level kits.