What is the plasma source - I use Hypertherm which is widely regarded as one of the best plasma generators out there.
I also use SheetCam for my CAM and various apps for the design, anything which can output a DXF file is good - InkScape, Illustrator, most CAD packages, and plenty of others.
You will need spare consumables for the torch - you WILL need these as they can be damaged by something as simple as a low pierce, pierce height - the point at which the torch sits the moment before starting a cut IS VITAL, get that right and repeatable before even plugging in the plasma source and it will save you $$$$$$
You WILL need a lot of scrap or other steel to practice on - don't go too thin, if you intend cutting say 3mm then practice on 3mm from the off - different thicknesses and types of steel WILL affect all of your settings.
There are a million and one other things to learn - it's taken me about 4 years and i'm still learning but can now churn out saleable parts in no time
Have you got a water table or downdraught table - different ways of dealing with terrible and dangerous fumes plasma tables can make, stainlesss steel in particular is bad, also aluminium, steel will just give you a sore throat and coat the workshop in black grime in no time at all