My question is related to the implementation and setup of the
environment as explained in the above example. How can I achieve this
considering that I have created an updatable m-view?

If possible, how do I push changes made to an updatable m-view back to
it's master table when/before I execute DBMS_MVIEW.REFRESH on the
m-view? What is the procedure to do this if both table and mview exist
on the same database? Do I need to create master groups, materialized
view refresh groups, etc.?

One more thing.. Is there a way to retain changes to the m-view during
refresh? In this case, only newly inserted/updated records in the
associated table would get inserted into m-view. Whereas changes made
to m-view records would stay as-is.

Hope my question is directed well. Thanks for your help.