Propane fitting question...

There's a few ways to get there.

What I would do: Remove the existing copper tubing and flare fitting from the pictured iron "tee". Install another iron "tee" with an iron nipple into the vacated hole. Reattach the copper tubing and flare fitting to new "tee". Attach another flare fitting and copper tubing piece to run to heater location. Somewhere convenient, I would install a shut off valve on the new copper supply tubing.

Swivel fittings aren't needed and are prone to leak. Hose isn't needed and is prone to rot and leak. Flare fittings seal with mechanical pressure, soldering isn't needed. Just asking that question makes me suggest that you have someone else do your gas piping. I think you'll be happier and safer having someone experienced tackle the job.

Bump

Sorry I'm a newbie with propane fittings... So if I got a 3/8" flare tee and a 3/8" swivel connector like these



Then I should be able to then run low pressure rubber/flexible hose along the frame and pipe into where I need it into the bottom of a cabinet to attach to the heater that has a 3/8" flare male fitting.... And of course caulk and seal the hole where I drilled for the line in the cabinet..

Also when attaching propane copper fittings do the need soldered around joints or do they seal themself?

That looks like a 1/2" NPT X 3/8" flair adaptor... Undo the flair nut, remove the adaptor and take to the hardware store and get the appropriate fittings and valve. They'll probably have a (BBQ) kit with valve with a quick disconnect and hose. I know Home Depot has them, I get then there all the time (I'm in the business).