Edit MKV files together, trim etc...

[The_Mole_UK]

I want to take an MKV file and edit it. Perhaps add a couple of chapters and edit it. Ideally retain the subtitles too.
Is there a program I can use free or purchase?
No idea what...

Couple I've tried, the encoding streams rubbish, size changes etc...

Thanks in advance...

[d00zah]

I want to take an MKV file and edit it. Perhaps add a couple of chapters and edit it. Ideally retain the subtitles too.
Is there a program I can use free or purchase?
No idea what...

Couple I've tried, the encoding streams rubbish, size changes etc...

Thanks in advance...

https://mkvtoolnix.download/