[Wine] New prefix vs default ~/.wine file with default app

[isaac]

Hello. 

There seems to be no instructions on how to tell ubuntu to use a new prefix for a file type, which might have previously been associated with another prefix. For instance, you can delete MS Office from one prefix and install it in a freshly made prefix. I'm not suggesting renaming prefixes, but creating new ones. 

I believe a new user defined prefix is not treated the same as ~/.wine. 

Is this true?

Thank you.