Hi,
The skylink map is here;
http://www.dfwairport.com/transport/connect.html
Total time form skylink A to skylink D would be 5 or so mins plus allow 5 minutes ot walk up and down from the gates.
Alternatively you could walk on the pedestrian walkway from A-B then to D.
D36 will be at the B end of the terminal I think.
The skylink is very efficient and quick. How long do you have to connect?
Regards
TBS