Needless to say (I hope) is you do NOT use a flame to check for leaks. I use a soapy-water solution in an old spray bottle.
'Proper functioning'? Turn on your gas appliances and see if they work. Also, try them all at the same time to see if your regulator can maintain flow (make sure you have a full tank at normal temperature). If you're just out of storage it may take a while for gas to get through the whole system... I turn off my tanks for winter storage and it usually takes 20 or 30 seconds to get from the tanks on the front to the fridge/stove midships and then a few more 'pilot out' failures to light the water heater at the back.
2015 Rockwood Signature UltraLite 8282WS Platinum, GY Marathon LRD, TST 507RV TPMS
2005 GMC 2500HD CCSB D/A, Curt E16, Prodigy P2, Garmin RV760LMT w/BC-20 b/u cam