How do i add subtitles to movies?

i have a mac mini intel and i would like to know how can i add subtitles or even audio of a different language to movies ? i found a site where they have subtitles in all languages for most movies… but i just dont know how to insert them into the movie folder ?

go to

there you can find anything you want about editing media files

lots of manuals to do all kind of stuff

Thanx I’ll give that a try…