I don’t understand, either.
If you’re wondering why you’re getting 404 messages, it’s because those files don’t exist. (WordPress uses PHP; it never produces a page with an ‘.html’ extension unless you upload it yourself.)
If your pages aren’t showing up in a search engine, it may just be that the engine hasn’t crawled your site yet.
I also think you may have some problems with your permalinks. See this post for help with that.