ok, you know how you have the stalk black piece holding in the stalk radio!!
use that around the steel sleeve around the aftermarket deck, bend the metal hold in pieces on the sleeve to adjust to the black trim piece tha comes stalk in the rex.
then if you have your stalk harness and the adapter to connect to the deck and the stalk harness, solder the two harneses together. heat shrink them or electrical tape the wires, and MAKE SURE no bare wires are shown.
and make sure you have the wires in the right spots like
red and red
yellow and yellow
black and black
green and green
green/black stripe and green/black stripe
purple and purple
purple/black stripe and purple/black stripe
so on and so on just make sure you have correct memory to where you can set it and it stays there when you turn off the ign.
and if you dont then you will have to wire up your own which is what i had to do on my old car.
its easy just takes practice i can install a cd player in a car now in like 30 mins not too hard!!!
on most radios the yellow is memory, red is positive, black is obously ground.
hope this helps you out man!