Sound problems on Ubuntu 18.04 LTS

[ian]

Hi folks

Sorry to keep bothering you all, but if anyone knows why the Ubuntu 18.04.3 DVD I burnt on my Mac is recognized by my Windows machine but not my Ubuntu machine, it would be very useful to know.
I followed the same process as this:
https://discourse.ubuntu.com/t/how-to-burn-a-dvd-on-macos/14015

Unless I can find out why my Ubuntu machine doesn't recognize it, I can't progress my sound problem.

Also am I right in thinking that the Live disk function is part of the regular install disk, and that there is not a separate Live DVD?

Thanks

ian