Transport the propane tank to the gas connector. With the help of an assistant carefully load the propane tank into the hand truck. Carefully wheel over the propane tank until it is about less than a foot from the gas connector.
Apply a small amount of pipe thread sealant to the propane tank threading and the threading on the gas connector from the house. Pipe thread sealant is sold as a cream in most hardware stores or as a thin white tape.
Place the tip of the gas connector into the threading of the gas tank. You might need to keep moving the tank until the gas connector goes in straight into the gas tank. Screw in the gas connector with your hand until it becomes too hard to tighten with your hand.
Secure the gas connector with the adjustable wrench until it is tight.
Mix water and soap at a ratio of 10 parts water to one part soap inside the spray bottle. Shake the spray bottle when its closed, to mix the water and soap mixture.
Turn on the gas valve of the propane tank. Spray the connection of the gas connector to the tank threading with the soapy water mixture. If you noticed any bubbles forming it indicates there is a leak. Keep tightening the connector until the bubbles disappear.