In general, if you want to create .htaccess code that will force files to be downloaded instead of opened you would use this .htaccess code to do that. Of course you would choose the file extension types that you want to be downloadable.
<FilesMatch "\.(mov|mp3|pdf|mp4|avi|wmv)$"> ForceType application/octet-stream Header set Content-Disposition attachment </FilesMatch>