5000 watt car audio system need help?

Yes, put the positives together coming from the front battery or the alternator hot (which ever way you do it). Put the grounds together and you can ground it to the chassis, but make sure it's free of paint and just BARE metal. You WILL need a bigger alternator b/c with that one you'll only be getting you about 1,160w of power. Just search for high output alternators and you should find a few sites that will have/make them for you. Good luck!