Title almost sums it all up, where is the factory amp in a 1996 mercury cougar, and what do i do if i install just a new head unit?

Ill be picking up a Kenwood KDC-MP538U tomorrow, and i know its compatible with my car, crutchfield includes all the tools and wiring harnesses needed, but im impatient and im just gonna go buy one locally tomorrow.

So if i install this head unit, does it use my currently installed factory amp? and what do I do when i buy an actual amplifier?