Install PHP file manager by including PHP files
Download the latest version of PHP version of Flmngr, then unpack it to some folder inside your website structure.
The location of where you unpack the files will affect to File Manager URL
urlFileManager parameter you will specify later on the client side. For example, if you unpack to
/var/www/flmngr, the URL of File Manager will probably be
flmngr.php file already contains the call required to serve incoming requests. So the only you need to do is to link with the client side (change URLs configuration in JS code).