Hi Ken,
Mine is a single screen but all the wires go in the correct places.
If you have a look at the Garmin instalation pages you will see that it mentions some different colour cable ties and where to locate them and in which hole etc. Start there and work outwards. I layed mine out on a bench prior to installation just to work out where it all went and what bit attached to what unit. If I might make a suggestion here, have a check of all the connectors to make sure that all the correct pins/cables are in the correct hols on the D subs. Because fault chasing later is a biblical faff!
Enjoy.
John.