The first thing you have to do is get it home safely. (I laughed and laughed when I heard this story). Apparently there is a vacant lot on the corner right next to the local WalMart. The employees at WalMart call this lot the Grill Eater Lot. There are several smashed up grills that ended up dumped in that vacant lot as their owners took the corner too fast and lost the grill out of the back of their pickup trucks (I totally need to drive over there and get a picture). So – a tip for the new grill owner – tie it down before you leave the store :-).
For metal and cast iron grill grates, coat lightly with a high temperature oil like Canola or Peanut oil – wipe off any excessive oil, install the grates and fire up the grill. Heat the grill on high and let it burn for ~30 mins. This will burn all the solvents and impurities off of the heating elements, grill grates, etc. Note that porcelain grates won’t need a coat of oil, but will benefit from the burn in process to remove any chemicals/impurities that were applied by the manufacturer.
Chefs and the cooks who know their way around a kitchen (or a grill) know how meat feels when it's raw and when it's cooked. The only way to learn this is to basically poke the steaks at different stages of cooking. Raw meat is almost squishy, rare meat is quite soft, medium rare meat resists your poking a bit, and medium meat springs back. Once meat feels firm, it's at least well done, if not completely overdone. Gently press a finger onto your steaks—being careful not to burn yourself—to teach yourself the difference.
Check the ignition system. Turn the gas off, and test your ignition button to see if it creates a spark. If both the pressure regulator on the gas tank and the ignition system are running normally (meaning the pressure regulator is tracking and maintaining correct gas tank pressure, and the ignition system is sparking and lighting correctly), you can finish testing the grill by turning the gas back on and lighting the grill up as you normally would.