Was told to change the .htacess file form .html to .php so this would work properly

My video landing page shows up fine on the computer that the video and landing page where edited on. The VSL shows up fine on a link sent from my computer but when I go to play the video it goes dark. Also mu button does not work it shows up like a broken link???

How do I handle this issue???

here is my .htaccess presently:

RewriteEngine On
RewriteRule .* – (E=HTTP_AUTHORIZATION:%{HTTP:Authorization})
RewriteBase /
RewriteRule ^index.php$ – (L)
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php (L)

What should the .htaccess file look like after added the code to it:

RewriteEngine On
RewriteRule .* – (E=HTTP_AUTHORIZATION:%{HTTP:Authorization})
RewriteBase /
RewriteRule ^index.php$ – (L)
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php (L)

RewriteRule ^(.*)index.(php|html?)$ /$1(R=301,NC,L)

Is this correct, Please let me know.