Insert into multiple tables.

[eluser]Ralanyo[/eluser]
I'm new to ci and this is probably an easy question.
I am building an app with a relational MySQL database.

I've been able to display data from related tables via the use of an active record join, but how do I insert into into related tables?

Do I need to learn to use an orm, can it be done with joins, etc...can it be done with active record or do I need to use SQL? Any help would be appreciated. Sorry for the newbie question.