Open the cylinder handwheel ensuring that your hand is around the wheel and not above it. This is in case there is a deficiency and the components are released under high pressure. As well, ensure that you are standing opposite the regulator apparatus.
When you fully open the cylinder handwheel you will notice that the cylinder pressure gauge changes from 0 to a value, the maximum of which is 2500 PSI. In this case the pressure is a little over 1000 PSI, enough to weld.
You should also pay attention to the welding voltage on your welding machine.
Some power sources allow you to set the Voltage. These "constant voltage" power sources are generally used for automatic and semi-automatic welding processes (GMAW, FCAW). With this type of power source, the voltage is set with a knob on the machine, and the amperage is regulated by the wire feed speed of the wire feeder. This is so because, with a small change in voltage, there is a very large increase in amperage. By speeding up the wire feed, the arc length is shortened, leading to a slightly lower voltage which leads to a much higher current. This higher current then burns off more wire.
We can see that this is a "self-regulating" system, preventing the wire from "stubbing" into the work piece. There are obviously limits to this. What complicates the voltage and amperage (wire feed speed) settings on this type of power source is that you can move between different "transfer modes" depending on your voltage, amperage and gas used as shielding, in the case of GMAW. Welding voltage primarily controls the arc length, which is the distance between the molten weld pool and the wire filler metal at the point of melting within the arc. As the voltage is increased, the weld bead will flatten out more and have an increasing width-to-depth ratio.
Use a voltage that’s too low and the wire won’t be sufficiently fused to produce a good weld. However, choose a voltage that’s too high and the welding wire is likely to overheat – also giving poor results.
Some power sources will only allow you to set the Amperage. These "constant current" power sources are typically used for manual welding processes (GTAW, SMAW). With this type of power source, the voltage is a function of the arc gap. The longer the arc, the higher the voltage. As such, you cannot "set" the voltage. It is a function of the welder technique.
The relationship V=IR (Ohm's law, where V = voltage, I = current, and R = resistance) holds across the arc but does not hold for the power source itself. With this type of power source, when the voltage is changed by the welder varying the arc length, the amperage does not change linearly as is given by Ohm's law. Rather, the amperage will only change slightly with a change in the voltage. Hence the name “constant current”.