* Moved to CMS Section
Your index page will automatically use your template called "index.php", and your individual pages will automatically use the "page.php", your posts will automatically use "post.php", etc etc.
It’s tough to say exactly without looking at your templates. But you have an index.html, so you just need to make that into index.php and put wonderful wordpressy things into it.
Here’s more on template hierarchy: