The WinNova editor, EVNEW, is quite excellent. My own plug, EVN Battle Arena, was created entirely on it, as were most of the other Windows plugins on the Add-Ons page. If you're just starting out in editing plugs, make sure to read through the EV Nova Bible, included with your download of Nova.
You may not understand all of it at first, but that's OK. There's a lot in there to get your mind around, and much of it will still be trial and error.
Also, if I may suggest it, if you're having trouble understanding something, then download a plugin that's already made that has a similar effect to what you're trying to accomplish. Open it up with EVNEW and look at everything that the plugin's author did to make it work, then try something similar in your approach.
Of course, if you get stuck, by all means I hope you won't hesitate to ask for help here. Nearly all of us are more than happy to help out each other, no matter the problem, just as long as you aren't asking us to do everything for you.
Welcome to EV Developing!
(oh, and reading the stickied topics = ++)