amp in 03 yukon

I am wanting to install an aftermarket amp and sub into my 03 yukon.  Where exactly do I install the inline converter and do I need to do anything with the factory amp? Thanks in advance

do you have bose? if you do you need to get the hi low converter from the center counsole. they should be the ones leading to the sub in there. usually its two about 14-16ga wires twisted. green twisted alongside a blue with black stripe running towards the right side of the sub. you have to take the cup holder out i forgot to mention so you can acces all this its the easiest way.installers do it best. we got the magic hands!

Thanks for the help.  I have decided on replacing the head unit with an aftermarket one instead and completly redoing all the wires and hookups to aftermarket.  Therefore getting rid of the factory amp and other useless items.  Thanks again anyways