Place the propane tank on level ground. Stabilize the tank with cement blocks.
Twist the valve on the top of the propane tank to the closed position. Twist the handle of the valve clockwise to close it.
Find the connection fittings that attach the propane hose to the propane tank and RV. Turn the connection fittings on both ends of the hose counterclockwise; this loosens the hose. Use vise grips if the fitting connection is too tight to loosen by hand. Pull off the hose.
Attach the new propane hose to the propane tank and the RV. The new propane hose comes with the fitting connectors installed. Align the hose with the fitting connectors to the stem of the propane tank, and to the RV fittings. Turn the connectors clockwise to tighten.
Turn the fitting connectors on the propane hose until they are hand-tight. Do not use vise grips when replacing a propane hose.