first thing, you have to have the earth lead connected to the workpiece .
the torch will be either a touch type which will start the arc when youve pressed the trigger and have the electrode touching the work , or it will be a torch that starts an arc when the trigger is pressed but unless it is held above the metal to be cut in the correct position the arc will go out after a couple of seconds if you dont have the torch in correct position and start cutting .
i presume you know you need a compressor to run the plasma cutter , with the correct pressure set , unless its one of the lateast plasma cutters with an internal compressor fitted .
depending on the type of cutting torch head fitted you will have to make sure the shroud ,electrode and nozzle are in place properly but i dont think those plasma cutters need any setting up much .
when cutting use a straight edge to run torch against if cutting straight lines and go slowly across the plate when cutting it .
there are probably attatchments available for cutting circles also , probably from starweld/parweld or starparts .
.
.