LPG is Liquid PG that converts from high pressure to low pressure so YES you must use a pressure requlator. So you need an adapter from your tank to your regulator or a new regulator or both.
Check Amazon etc for all types of adapters. Suggest you get help as it's very desirable to have the correct connections.
2009 Holiday Rambler 42' Scepter with ISL 400 Cummins
750 Watts Solar Morningstar MPPT 60 Controller
2014 Grand Cherokee Overland
Bob