Where can I learn quickly the differences between using SQL Server 2008 and Toad for Oracle?

I am having trouble, the SQL in Toad software isn’t the same as the SQL I know from SQL Server. Is it? I have to get used to work with Toad for Oracle after several years I worked with SQL Server only.

I am looking in Toad if there is anything like the Diagram option in SQL Server? I mean, see the tables and fields and connection between them in diagram. Is there anything like this in Toad? I didn’t find.