To be honest, I don't personally know anyone that has installed an equalizer into their car, hopefully someone else can help you. Have you looked at the manual?
EQ sits between the head unit and the amp. Head unit ----phono lead------EQ INPUT, EQ OUTPUT--------AMP INPUT. Are you fitting it to a car or making your own sound system. You do know this is a mono amp, so no stereo? (Great for driving a subwoofer).