New Driver questions.

Hey there,
I have several questions about my new truck and job since they have several firsts for me...

The truck is:
Freightliner Business Class M2
Cummins 6.7L
Auto Trans
Air ride
Air brake
Exhaust brake
36' box truck
Single axle
Governed @ 65mph
And a Wabco Collision Mitigation System.

I haul bulk mail to and from distribution centers. With that said no real heavy loads. But heavy enough to be dangerous. My training was minimal to non existant, so the questions may seem stupid to some but please just post serious answers.

Best way to maintain safe speed on steep downgrades.

Winter driving tips, other than obvious.

Proper seat adjustment, I can seem to get comfortable in this sear, but first air ride.

Using air brakes, properly

How to use exhaust brake properly

How to load, heavy toward cab or tail, for better handling.

And climbing large hills. This truck shifts down and then struggles up hills empty. 35mph. Im on a time restraint and makes it difficult to meet my deadlines. Really confused me, an international I drove had no problems climbing at 65 with less horsepower loaded lol. Thought maybe something I'm doing wrong with auto trans.

While I'm not new to driving, im very new to this truck. It seems extremely light and likes to walk when empty. Also my first auto trans bulk truck, and it just seems timing is off between 3rd and 4th... drops below 1500 rpms... and lugs hard when going up hill empty. Any advice will be greatly appreciated. My stretch of road is I 79 ,I 70, I 376 between Morgantown WV and Downtown Pittsburgh.

Thanks guys.