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The new Bilstein 5100s are bolted in place. As you can see, they are mounted upside down for less unsprung weight. Although a beam axle is so heavy that the difference is small, you are removing several pounds from the total unsprung weight from the rear wheels. Less unsprung weight helps both ride and handling.On this truck the shocks are staggered, one in front of the axle and one behind it. This controls leaf spring windup better, reducing wheel hop and improves traction both off the line and out of turns.
The rest of the mounting hardware is pre assembled on the Big Wig air spring.
The Big Wig air spring is bolted to the chassis, then bolted to the axle via brackets that are held on to the axle tube with wrap around brackets.
Here is the Big Wig spring in place. Our truck had a 1″ lift block but the 5100 Bilsteins and the Big Wig air spring easily accommodated that. 
The Big Wig air spring mounting bracket had a rock and debris deflector built into it, a nice touch in case you are going off road. 
This sturdy bracket for the rear swaybar end links wraps around the cross brace on the frame.
