The negative resistance regime of a plasma discharge creates a particular type of self organizing macro-EVO or complex space charge configuration that allows for the production of massive quantities of excess energy. Here are the three steps.
1) Build a reactor with two electrodes, ports for inputting gaseous fuel mixtures, and a circuit and power supply that is tunable.
2) Once fueled up, start the discharge and enter the negative resistance regime without going into a true arc discharge. (The fireball, complex space charge configuration, or macro-EVO will form during this period.)
3) Tune the system into resonance by changing the parameters of the circuit and system. This will make the fireball that initially appears on the surface of one of the electrodes detach and become free floating. You can tell you are in resonance by looking at the ion acoustic oscillations on your scope.
The above is the basic information you need.
Yes, there are all sorts of practical considerations and nuances. Yes, there are a wide variety of fuel combinations you can test. Yes, for the sake of safety you should take all sorts of precautions. But we have THREE different companies, right now, utilizing variations of the above steps to build WORKING systems: Brilliant Light Power, The SAFIRE Project, and Andrea Rossi. If you do more research, you will realize there have been many groups that have utilized this same phenomena going all the way back to Nikola Tesla. George Egely had discussed these systems in his articles.
What's important to note is that by utilizing these basic principles, individuals have been able to get plasma based systems to produce excess power in multiple forms over and over again. It's not really that difficult! Obviously, someone with no hands on electronics experience would have a tough time designing the power supply. But for a small team with a couple competent individuals that have a background in fabrication and electronics, it should be FAR simpler than building a powder based system.
Once you can perform the above three steps, I'd suggest that you look at commonalities between successful systems. From this you'll learn that these systems work best when HYDROGEN or DEUTERIUM gas is in the mixture. Secondly, you'll learn that small percentages of noble gases will help stabilize these plasma balls. There are all sorts of fuel combinations that could be tested. The general theme is that combinations of gases with different atomic weights help produce different sheathes or layers within the "onion" of these macro-EVOs.
Be aware that once you get such a system going, you will see many anomalies including excess energy (in the form of light, heat, and electricity), surges of a strange type of electricity that goes back into the power supply, emission of longitudinal waves, emission of "strange radiation", and more.