In KMP, Play the video, drag and drop the subtitle. You should get a confirmation in yellow text saying the subtitles were loaded. if you can't see it, press alt-x to toggle show/hide subtitles.. If you still can't see it, it might have gone below your overlay surface, try repositioning the subs by right click > subtitles and some options.. All these if you are using KMP.. If not, use KMP..
Its a free media player.. Damn good.. Plays anything.