1...Are you amplifying the Aftermarket Speakers with a 4 channel amplifier?
NO, IT'S 2 CHANNEL
2...Are you putting the amplifier in the rear?
3...Are you asking how to run the amplifier wires to the new speakers you have?
YES, so so.
4...Do you have a "crossover" attatched to your compnant speakers you purchased?
YES, A CROSSOVER.
5...Also do you have a link to your products you bought? (amp,speakers)
IS IT IMPORTANT?
If your using a 4 channel amp thats placed in the rear of the car and have a pair of componant speakers with a crossover, this is what you do.
Take the car apart from the rear plastics, seats and front doors to make it easy to run wires.
Run the power wire of the amplifier on the left side of the vehicle and connect it to the battery through the firewall with an IN-LINE fuse. Run two sets of RCAs from the rear on the right side of the vehicle and connect it to the rear of the CD player. Also on the right side of the vehicle run your Blue Remote wire with the rcas, connect that to the blue wire thats connected to your cd player, sometimes the wire is blue with a white line. After doing this use speaker wire to go from the amplifier to your componant speakers crossover box into the Input. Then attatch the wires from the tweater to the 1st speaker ports. Then attatch the woofer to the 2nd speaker ports. Then the last speaker port connect the factory positive and negative (from the speaker plus)to it. Most crossovers have 4 ports to use.
I didnt proof read anything i wrote but that should be all you need to do. Good luck and if you have any questions just ask
OK, NOW I GO IN THE CELICA.