Can't browse for subtitles, if want try to "fake" as downloaded then put on
/sdcard/subtitle_download/exact_same_file_movie_name.extension/any_subtitle_files
Example if video file name is Avatar (2009).mkv
/sdcard/subtitle_download/Avatar (2009).mkv/doesn't.matter.the.name.srt
/sdcard/subtitle_download/Avatar (2009).mkv/doesn't.matter.the.name.en.srt
/sdcard/subtitle_download/Avatar (2009).mkv/doesn't.matter.the.name.ass