How do I create my own mods?(for Civilization IV users)?

i have civilization IV Game of the year edition. how do i create my own mods? i ask this because i have tried to download quite a few mods from filefront.com but, every time i do, they're zipped and i try to unzip them but then they just completely disapear. i tried downloading a starwars mod yesterday but after it finished idk what happend to it... is there something i'm doing wrong? or do i need to download something to download? and do i need to download anything in order for me to create my own mods? plz %26amp; thnks...How do I create my own mods?(for Civilization IV users)?
If you're using downloaded mods, make sure it's compatible with your version. Looks like you have the basic Civ IV, called the "vanilla" version. Most mods are for the exapansion packs Warlords (WL) or Beyond the Sword (BtS).



I played vanilla C4 for about 3 months, beat a few of the scenarios, then upgraded to BtS. It is WORTH it! Unlike most expansion packs, which are ripoffs and only improve the game by about 10%, BtS is almost a completely different game. First, the basic gameplay is improved, with better balance and tactics. Second, the AI is a bit smarter. Finally, the mods that come with the game are "mini games" where the rules are changed and some don't even feel like C4 anymore. Like Afterworld, where you control 5 commandos in a tactical format. And if you like Vanilla C4's WWII scenario, you'll love the Road to War Mod series, where you can play as many more of the WWII parties on both the Europe and Pacific theaters.How do I create my own mods?(for Civilization IV users)?
you can't becuase a game of the year edition is made to stop all of that stuff