Need help to view all Schemas using SQL plus

Hi, I'm not very familiar with SQL plus or DBA side of stuff. Our server got hacked into and so trying to do some salvage operations. I need to know what SQL commands or script I can use to view and retrieve all the scemas and tables in my database. I am accessing it through SQL worksheet. I would really appreciate any help I can get. Thanks.

I don;t know SQLworksheet, but if you log into the database as SYSTEM (or another ADMIN) and:

SELECT DISTINCT owner
FROM all_objects;

that will give you a list of all user that own somthing and starting point (I guess you don't care are vew only users - look in DBA_USERS)