Welcome to Cnczone, there is a plethora of information here for people just like you. I, too, got into this hobby knowing nothing about CNC plasmas other than I wanted one and couldn't afford to buy one. Now, I have built one 4x4 plasma, and am now building a much larger table.
Check out the build logs here in the Cnc plasma subforum, see how others are doing it, or contact other members for specific building and construction questions.
Many others here have built machines, in a variety of sizes and budgets.
You can also stop by the plasma chat here on the Flashchat of this site, every Saturday night at 7:00 PM, central time. We usually have a lot of build and construction discussions, as well as software and use tutorials. Feel free to sit and learn.