You can find info and instructions online at Lippert Industries. Seems like only having the outside lights is overkill. And, by your trailer description, you should have many more functions on the remote. The generic pin is usually 0000. You can set your own personal pin.
On our Timber Ridge, we can do the main slide, closet slide, awning, front and rear stab jacks, and the exterior light. All functions are on 2 screens. I definitely you should have more than just the light option.
Here is one Lippert file that may help:
http://www.lci1.com/assets/content/support/manuals/Linc-Remote-System-Owners-Manual.pdf