Stock stereo, amp, sub?

can anyone tell me how or where to find info on how to wire an amp and sub to a stock stereo?

You need to be a little more specific. What speakers do you plan on running off the amp will you be adding subs? Also what kind of car and what year? But most likely you will need what is called a high to low converter. The converter will convert your head unit’s high input signal to an rca low output and from there you will run the rca cables to the amp(s) supplying them with a signal. Please give us some more info so we can assist you in your install.

well i was plannin on running stock speakers and adding an alpine amp to power an alpine sub on an 03 eclipse

What you need to do is get a high to low converter and splice that into your rear speakers. This will convert that signal to an rca cable which will then supply your sub amp with an input signal. For your power you will need to find a + 12 volt switched ignition source for your remote wire connection on your amp. The remote wire is what turns the amp on and off. You will also need to run a fused(must be fused within 18 inces of battery) + power cable from your battery to the amp. As far as the ground goes you will need to find a good grounding location near where ever you decide to mount the amp. The ground should be no longer than 18 inches long. I would suggest that you ground it to the chassis just be sure that you sand it down so you have bare metal.