For Natural Gas:
1) 3/8 NG hose and a needle valve to adjust the flame size. I use brass 45deg flair fitting for the hose ends and the attachments at the BBQ and house.
2) Fire ring/bar. This is the distribution system that is below the grill for your gas. If you have the ability to weld and make rings you can make your own using a 1/2 weldable (not cast iron) coupler in the center, 5/8 thin wall tubing for the ring and drilling 3/32 holes every 1 1/2". The ring should 1/2 - 1/3 the size of your BBQ container diameter.
Stainless steel will prolong the life of the ring especially during the winter when you forget to cover your BBQ in the first rain. I've heard of people using copper too.
3) BBQ Fittings: A 1/2 NPT brass bulkhead coupler and 1 1/8 lock nut, or a 1/2 weldable steel coupler, Brass1/2 to 1/4 reducer, 1/4 street 90, neddle valve, 45 deg flare (for attaching the hose to)(not used in this build), brass 1/2 NPT nipple (to attach the the ring to the coupler welded to the container)(not used in this build).
4) House Fittings: all brass; 3/4 to 3/8 reducer, 3/8 street 90, 3/8 nipple, 3/8 ball valve, 3/8 to 45 deg flare for attaching hose to BBQ.For Propane:
1) Regulator/hose 1-30 PSI (not a BBQ regulator, too small) and a needle valve to adjust the flame size. I use brass 45deg flair fitting for the hose ends and the attachment at the BBQ. BBQ propane tank. You will need a venturi
if the propane flame is too smoky. Alt
.: Home Depot sells replacement BBQ parts. Buy the reg, hose, burner and install in your charcoal grill.
I've put together an affordable kit
of the basic plumbing supplies you'll need to build a fire pit. This kit could be used to build a BBQ as well.
I offer several sizes of rings, stainless upgrades and fully auto systems for high end remote controlled fire pits.Fire Pit Kit link