Hold #1 and #3 down on the overhead, until the display starts blinking.
Then, press and hold the OEM transmitter button and the desired button on
the overhead for a few seconds (the display will either blink, or will
change the rate of blinking - going from memory here).  If your opener uses
a rolling code, you have to put the receiver into learning mode (consult
your opener's manual), then press and hold your Durango's transmitter button
until the receiver indicates it's learned the new transmitter (again,
usually a blinking light).  Note that on most openers, you only have 30
seconds to transmit once you put it into learning mode, so you'll probably
need two people.

Incidentally, if you want, http://www.techauthority.daimlerchrysler.com 
sells owner's manuals for $10