illuminated entry for 98 dodge ram

alright, i know there is a wiring diagram for this on the site but i kinda wanted a little more insight than that.  Here is what i got:

1.  Dome Light Output from alarm system (negative)

2.  relay

3.  my interior lights in my truck are very simple.  Three wire hook-up.  One is a ground, but im not sure what  powers the other two.  The light setup is the kind where if you open the door they come on and stay on constantly (obviously), but after you shut the door you can push on them (there are two lights side by side)and that will turn them on/off.

i was guessing that one of the three wires should be hooked up to the doorpin and the other one (besides the ground) would be a power wire for when you want to manually turn the lights on by pushing them.  So i figured if i tapped into the wire that had power when the door was open and used that to wire up to the relay it should work out, but im not positive.

so yah, bring on the idea's because i just want to make sure im doing this correctly.  Thanks.

alright, im following you.  Except for the CTM part..heh.  What exactly is a CTM?