Editing Button destinations

On my checkout screen, for some reason the billing and shipping address buttons are going to the site home page, and I can't seem to find the backend code that designates where these go to, or what the code behind them should be. Help would be appreciated...thanks.

That sounds like a javascript error on your website which prevents the popup system of Joomla to be initialized and thus you don't get the popups for the address edition when you click on the buttons.
I would recommend you to check your browser's javascript error console for the error and fix or remove the extension generating the error(s).