Obtain the appropriate wire from your local hardware store. The wire should consist of the same kind of metal as your base metal: if welding stainless steel, use stainless steel wire, and if welding aluminum, use aluminum wire. If welding carbon steel, use flux-cored carbon steel wire for outdoor conditions and solid carbon-steel wire for indoor conditions.
Refer to your welding tool manufacturer's guidelines to determine the appropriate thickness for your wire. Thinner metals need a thinner wire, while thicker metals need a thicker wire.
Adjust the wire feed hub tensioner so that the wire is held just tightly enough that the machine can feed it, but not sufficiently loosely that it can slip.
Strike the welding electrode on your base metal to start an arc between your welding tool and the base metal. Allow a weld pool, of molten metal, to form as a result of the heat. Direct the wire to the leading edge of the weld pool.
Hold the gun straight as you weld, to obtain a steady weld with constant wire feeding.