Speakers to amp to head unit

Im re wiring my whole system in my car. I have bought a 9 wire to run from my amp to my head unit for the speakers but also want to redo the actual door speaker wire itself. Do i tie the 9 wire from the amp into new wire from speakers and then tie it all in behind the head unit? Might seem like a dumb question but never ran door speakers off an amp before so wanna make sure its right. 

Thanks!