i have 2 amps a 2 channel and a 1 channel how do i run the two wires to the box for my 2 thunder 7500's do i just take a positve from one and a negative from one or do i just run a positive and a negative from both of them and then splice them i dont no im lost and the rca wires for bothy amps how do i do those if you no either part please let me no