Beginner Help - How to get domain.com/Dashboard/Campaign/ID/Contact/ID URI

[eluser]joshlindsay[/eluser]
[quote author="InsiteFX" date="1377275703"]Dashboard controller.
Campaign controller and model, database table campaigns.
Contact controller and model, database table contacts.

[/quote]

Excellent. That's what I've got so I'm on the right track.

How do I get access to the Campaign and Contact controllers and functions from the Dashboard?
Do I need to run a check to see if segment 4 (contact) is NULL - if so load Campaign if not load Contact?

Is there a specific topic I should be researching to find my answers?

Thanks