extract main title from full backup?

[shisha0505]

Ok, so now i've got a full backup of a 3D-blurays.
It is not an ISO but a backup just as it is created by makemkv.
How should i proceed if i wanted to rip just the main title with some additional language audio and subtitles from that backup?
I thought i simply could load that backup into makemkv and then edit the movie just as i would do do with a physical BluRay disk that is loaded into makemkv.
But unless i miss something there is no way to load the backup into makemkv.

Any hint is very much appreciated

[Ezatoka]

You have to select "Open files manually" and then select the index.bdmv file inside of the bdmv folder

[shisha0505]

Many thanx,
i don't know if it ever would have occurred to me to try something like the index.bdmv file