Newbie to this forum & to owning a Cummins

Newbie to owning a Cummins. I've leased for the last 5 years so I wasn't able to upgrade, or had to cover any repairs. Just purchased a 2016 6.7 LB CC 4X4 3500. 190k miles. I don't know anything about this truck. Its got (I was told) 2" lift with leveling blocks in the rear. It's got Toyo 35 x 12.5 R18s Open Country AT on some Black Rhino wheels. I just Rhino lined the bed. Had a back up camera and double din stereo installed as well as a remote start.
This truck will be mixed use. I tow around 12k-15k on average 2 or 3 days a week. Some weeks more some less. Wanting to know what I need to do to keep this thing running the best.
Any info and insight is appreciated.