请问怎样用subtitile的file (sub) ??

alantct

i hv a movie file, Lelio.Po.Po.2010.DVDRip.XviD.ONiE and another two files (seprate) is the sub  & idx file. may i know how to use or combine the video file so that i can watch it with subtitle ?  
/ S2 \1 _9 G  X/ E7 h+ Gtvb now,tvbnow,bttvb! n; f! c8 z: z
thanks in advance.