If you havent gotten it yet.
Red - Hook straight to battery terminal and run it all the way to the back where your subs will be, either through the side of the door or drill a hole in the firewall.
Ground - Theres bare metal under the back seats just unscrew one of the screws and put your ground on that and put the screw back in to hold it.
Ignition(blue) - With your aftermarket HU there should be a blue wire coming from the wiring harness directly from the HU it shouldnt be hooked to anything and if it is just splice it in.
Speakers - there should be RCA outputs (red and white) on the back of your aftermarket HU hook up some RCA wires for car audio and run them to the back to your amp. Your amp should have positive and negative run those to the subs with the correct wiring. It would be beneficial to buy a amp wiring kit and capacitor from walmart or another car audio source.