Ouch...This would take three pages to tell you how to make the basics of a plugin.
To put in short, download the latest "EV Bible" (it applies to Override as well), and "ResEdit." Those are two ot the most powerful programs you'll find, ResEdit in particular. The EV Bible will explain how to use ResEdit. Or if you want, get the "ShipWrite" program. Making ships is easy with this program. All this is put in short, but hope it helps. You can find all these applications in the add-ons page of the Ambrosia website.
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~Captain Skyblade
President of the Corsair Development Team
(url="http://"http://artworks.tmgmedia.net")Corsair Homepage(/url) | (url="http://"http://pub57.ezboard.com/bcorsairdevelopers")Corsair Web Board(/url)