I want to install car alarm and remote start up system by myself. However, I don't know how to start. I want to buy a system like

http://cgi.ebay.com/AUDIOVOX-PRESTIGE-REMOTE-START-CAR-ALARM-APS-787-787A_W0QQitemZ350108011669QQcmdZViewItem?hash=item 350108011669&_trkparms=39%3A1|66%3A2|65%3A1|24 0%3A1318&_trksid=p3286.c0.m14#ebayphotohosting

How do I know whether it will fit my car? How to remove the cover of the car to start to install? How to know where each of the wire in the car ??

Thanks