Good make Cebora, had a couple of them in the past. Basically you have a spool of wire fed through the gun which melts the steel being welded. The arc is made by connecting the earth clamp to the job. If it is a gas mig, you will need a bottle of inert gas which will need a regulator fitted to the bottle and a small hose will take it through the gun and the gas protects the area round the weld. If it is a turbo mig/gasless then it wont need a gas bottle. The welding wire is different for a gasless mig though, it has a flux in it.