Hi. Picked up a 04 Tremor radio, would like to swap it to my 04 Edge to replace cassette/cd radio. One plug matches up, and powers the unit up but I do not have the plug for the amp/sub on the Tremor radio, what do I need to do to get sound, really dont care if I have a sub or not

 

Ranger Radio wiring diagrams here: Ford Ranger Radio Wiring Diagram

There were 3 different audio/radio options in '04, you first need to know which one you have.
Basic has amplifier in the "head"(radio) unit
Other two have separate amp which you may or may not need.