How do I bypass a buick rear speaker amplifier?

Ive installed a deck n subs and come to find out my rear 6x9s dont work I was told I need to bypass the amp its a 97 buick park ave|||either run a direct wire to the back from your head unit to the speakers, but if there is a speaker wire already connected, find the amp next to the speakers, figure out what the power is and disconnect, and disconnect the speaker input to the amp, and run it directly to the speaker.