It's not that hard.
1st take a measurement from the center of the front hub to the lower edge of the fender well (above the tire). this will give you a baseline measurement.
2. Jack up the truck at the frame rails taking the weight off the front tires and suspension.
3. Under the truck there is a crossmember that houses the adjusting keys for the torsion bars. At each end of these keys is a bolt. This bolt controls the ride height of the vehicle. Tightening this bolt will raise the vehicle and lossening it will lower it.
4. Take a mental and written note on where this bolt is from factory. Tighten this bolt in 1/4" increments equally on each side.
5. Take vehicle off jack stands. Jounce the front end of truck rigorously to settle the suspension and take your measurements.
6. Repeat steps 4 & 5 until desired ride height is achieved.
7. I personally advise not to top out ( crank the torsion bars to maximum) the suspension, as it is harder to align ( not enough adjustment of the upper control arm) and is harder on the upper ball joint due to the increased angle.