so when you say builder_page.php do you mean the pages because I don't see anything else that's similar?? 

I showed you the path to the settings, just paste this into your website’s browser.

I typed /studio/builder_page.php?type=system&page=sys_home and it navigated to Pages.  I was already in Pages.  I'm not sure where it is possible to add video to home page there.  Can you elaborate or take a screen shot.