Have I lost my mind??? Newbie

I have been trying for at least a month to get linux running in a VM on my iMac. I believe that I have downloaded and installed ever first level flavour in the world, BUT......
I must me an idiot. Proficient with Windows amd Mac OS, I don't seem to be able to get ANY data into Ubuntu. I cannot see any drives attached to my iMac nor can I find anything on the main mac partition. Have messed with samba, guest app, etc. etc. Dose Ubuntu maintain a war criminals data base? How about really unattractive men?

I can't figure it out.

Surely it can't be that hard.

Thanks in advance.
Cheers