FIRST OBVIOUS THING TO DO IS SHUT THE VALVES OFF IMMEDIATELY WELL DUHHHHHHHH and dont open or close doors or turn on or off anything electrical or make any sparks whatsoever anywhere near the unit... Is it the old left hand threaded POL or the later OFPD fittings that attach to the tanks??
Many regulators have a removeable cylindrical cover under which you find the screw down/in adjustment, tighter in greater the pressure, but that adjustment is for a trained tech with a pressure gauge, NOT something for Billy Bob and his know it all brother in law Bubba to guess at in my opinion !!!
I use a small mist sprayer filled with hot water and kitchen sink soap to spray on and detect leaks. If it is the regulator, they are relatively cheap and plentiful at your local LP Gas dealers or on Flea Bay (Marshall Brass comes to mind). I use teflon Tape on threaded pipe connections. Those gas piping/plumbing fittings arent really rocket science but have parts good n clean.
If you have like dual tanks, the combination regulators with auto switch over valves when one tank empties are great.