Welding for the first time - need advice

Easy to tell if you have gas. I'm not familiar with your welder, but they all have a tension device on the wire feed. Either turn the wire speed all the way down, or loosen (unlatch) the wire tensioner so it won't feed.

Hold the gun near your ear, being careful where you point it. When you pull the trigger you should HEAR gas flow. If you have a regulator with a low pressure side gauge, it should drop a bit with the trigger down. If you have a flow gauge, IE a "floating ball" etc, it should show flow when the trigger is down. You should hear a fairly loud thump for the gas solenoid.