Need help installing and rewiring stereo in a car?

I have a 2001 civic ex 4 door and the jerks who had it before chopped most of the speaker wires that go bellow the carpet to the speakers on the back and even the ones on the door. My question is how do I connect the wires to the speakers after I try to extend the shopped wires. Does someone know the colors for the stock harness because I will need this when I instal a new harness for it since mine has the wires but the oem harness is gone How do I know what speaker will lead to the right or left speaker that sort of thing