Install is really up to you. Hack the old muffler and tailpipe out, clamp or weld the new muffler on, need to get a hanger in there since you just eliminated the stock muffler hangers.(see pics below).
Me personally, I believe in adding larger cat-back pipe..bump it up to 2.5. Bigger pipe aides in breathing better and changes the tone too...deeper. I originally had a single 2.5 done up a few years back...then made seemingly constant muffler changes til I found one I liked. lol. Ran it dumped(nothing behind the muffler for like forever). Then I did a full new setup with 2.5" incoming pipe into the muffler, then dual 2.25" tailpipes. I used a 3" in/dual 2.5" out Super44.
Get an offset in muffler definately.
Here's what your setup could look like.....all my old mufflers went to friends and I installed as follows....used a $2 hanger and a 3/8" bolt through an existing crossmember hole....then some $1.50 clamps....Stock pipe should be 2" for your truck...IDK if you can get Super44's in 2"...so you may need to use a reducer to make it all work like below...