Set up you propane gas cooker on a flat surface and connect the propane tank to the cooker. To do this, first find both the propane tank valve control--the nozzle on the propane tank that either releases or stops the flow of propane gas--and the cooker's regulator valve control--the nozzle on the cooker that either blocks out the propane when the it is in the "Off" position or lets in the propane gas in when the it is in the on position.
Make sure the propane tank valve and the regulator valve on the cooker are both turned off. Depending on what type of propane cooker you have, there may be an "Off" position or you may just have to twist the valve to tighten like you do a outdoor water faucet to turn off a hose. Refer to your owner's manual.
Connect the propane tank and cooker together with the small hose that came with the cooker. To do this, use a wrench to tighten the end of the hose to the propane tank valve. Then use the wrench to tighten the other end of the hose to the cooker's regulator valve, the opening where the propane gas comes through into the cooker.
Make up a bucket of very soapy water with your water and dish soap using one part dish soap to three parts water. Put a generous amount of the soapy water all over the hose and both propane and cooker valves. Now turn the propane tank's valve control twice to start a good flow of gas. Open the cooker's regulator valve all the way. Look for any bubbles coming out of either of the valves or the hose. This indicates a gas leak. Stop the leak by tightening the hose around the valve that is leaking gas with a wrench. If there is a leak in the hose, replace the hose with a new one. Keep the valves open for ten seconds or fewer during this test, and make sure the valves are completely turned off after the test.
Fill your pot or pan with water, oil, or whatever you plan to use to begin cooking. Make sure you don't fill the pan more than halfway full to prevent splattering. Set the pot or pan on the ground so that you can start the cooker's fire.
Turn the propane tank nozzle twice to start the propane gas flow. Light a match and hold it about half an inch above the burner port hole, the pilot that you light to start the cooker. Slowly open the cooker regulator valve until the cooker lights. If the cooker doesn't start after 5 seconds, turn off both valves, wait five minutes, and then repeat this step again until it is lit.
Place the pot or pan on the cooker and cook your food. When you have finished cooking your food, first turn off the propane valve and then the cooker regulator valve. Wait for the cooker to cool before you store it.