audio setup

i'm planning to setup an audio system on my pick-up truck, but i'm very new at this. can someone pls show me a diagram of where the following items should be placed and its purpose. thanks.

-capacitor, circuit breaker, crossover, fuse etc.

Capacitor: should be placed on your store's shelf and your money remain in your pocket.

Circuit breaker and/or fuse: used to protect the main power cable running from your battery to your amp.  This device should be sized for the capacity of the wire and placed as close as possible to the positive battery terminal.

Crossover: used to distribute the audio spectrum frequencies to the proper speaker so that each is used to the best of its capabilities.  Active crossovers are used in the line-level signal chain between the pre-amp (your head unit) and your amps.  Passive crossovers are used in the speaker-level signal chain between the amplifier and the speaker it is designed for.

I highly recommend you either get assistance from a pro in your area, or if you want to try and do things yourself, start reading everything you can absorb from THIS web site.  Cheers.