Garage heat, need advice Options

[Sparky]

A friend recently remodeled a small office and gave me the direct vent propane heater that had been used there. It's an Empire Gravity Direct Vent with a blower and thermostat. Can I just pick a wall and stick it in place with something like this as the cap/vent:

Simpson Dura-Vent

Or do I really need a whole chimney setup for it?

It's a 2 car garage that is decently insulated. I plan on keeping the tstat set to about 50 and bumping it up before I head out to work in the garage. The local propane company will "lease" me a 100lb. tank for free as long as I order 100lbs. of propane a year. I dont see that as an issue as I'll plumb it to the heater and my gas grill. Which brings up the next set of questions, what do I use for propane line? Can I pick it up at Lowes or HomeDepot? Trying to keep the budget down to avoid the dreaded S.S.S. (Screaming Spouse Syndrome).

Any and all advise greatly appreciated!!

My best,
Mike D.