mkvtoolnix sub and idx subtitles

[rr1]

Hello, im trying encoding a mkv file with the subtitles.
The problem is , to watch the mkv file I need those two files, one is idx, and the other is sub file, the problem is that I cant open the sub file, and only the idx file, I tried encoding idx file, but it doesnt work, I only have half of the subs, any idea how to encode with both of them?

[Mosu]

Just add the .idx to mmg and it will read the corresponding .sub automatically. You cannot add a .sub directly.