The FGA for oracle 10g/11g

Dear all,

I read this http://www.oracle.com/technetwork/articles/sql/week10-10gdba-097438.html

and I am not sure how to turn the FGA on and why should we use this instead of "after insert/after update/before and after delete trigger".

 We need to do data level auditing for the after insert/before and after update/ before and after update and save the log to another table.

  it seems that before change value and only commited vaule has to use trigger instead of this ?

 I know this could create a large volume of data though in the SYS.AUD$ and/or SYS.FGA_LOG$ tables.  And by default these tables are inin the SYSTEM tablespace.

 So, if I use FGA, I need to either move these tables out of the SYSTEM tablespace.
 
  if we install Oracle on top of Windows,  where can we find these folde from Toad for Oracle?

  How to move the record from that default location and save the FGA result to a dedicated table store in a separate tablespace?

  Also who to :

1) Turn the FGA on ? just do the audit_trail = db_extended in the parameter file ? where is the parameter files ?
2) Once FGA is on, how to setup the insert/update/delete trigger.
3) it seems the FGA is the extention of standard audit ? and I must turn on the standard audit first? how to do it? once standard audit is on I just need to do the audit_trail = db_extended in the parameter file, that's it ?
4) standard audit use DBA_COMMON_AUDIT_TRAIL and FGA use DBA_FGA_AUDIT_TRAIL, how to make use of it?

is what tells from this article is true :

http://wingsinwk.wordpress.com/2010/05/24/oracle-database-audit-trail/  ?