www.makemkv.com

I'm a new user here - I mainly rip music DVDV and DVDA discs
I started ripping some discs and the first few produced 1 file, which is what I want.
Then for some reason it's started producing individual tracks.
How do I rips a disc to a single mkv file?

That depends on how the disk is authored.

If it is a single title, you'll get one MKV file. If it's a collection of titles, you will get one MKV file per title.

When the disk author elects to go with individual titles, you would have to combine them after ripping. There are tools to do that (search for mkvtoolnix).