Garmin ZUMO 450

[rabbit]

:-/Just received a Garmin ZUMO 450 and have some questions .
To hear the audio sound, do I need a Blue Tooth receiver? I only want to hear the directions, not talk on the phone. I plugged in a reg. speaker in with no results. I also wany to use it in my truck with some kind of a speaker set up. What in, outs, & tricks do I have to know to get the best use of this gadget. Any help will be appreciated a I am a old newcomer to the electonics world.