SQL & PL/SQL

hi..good morning to all...

I have a schema ABC which owns some objects.
Now some days before I have made another schema XYZ which was a replica of ABC schema.

between these days some new tables, new columns in the existing tables(with or without default value), comments on the columns are being added in the new schema i.e XYZ schema.

Now I have to find the extra things which are present in the new schema. I need to find the new tables, new columns in hte existing tables, their default values and descriptions of those.

Can u plss help me how can I find it?
I am guessing that I have to write a SQL query with a minus clause but I am not able to write it and also dont know where should I execute it.

plss help. thanks in advance.