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I am new to blue host and I need to know how to set the default index page for my web server. Where can I choose between index.html/index.asp/index.php etc… and tell the server to default to a index.php over a .html?

I am running wordpress. In a boob move, I deleted the file default.html from my public folder. Any help as to how I can get it back or reset the file would be appreciated.