This is a case where "Google is your friend". Google "LCI 358601 pairing instructions" and several sites will come up that give complete instructions.
Here is one PDF file location:
https://www.lci1.com/images/support/lipsheet/0307.pdf You can download the file, save it to your phone or laptop and have it available where ever you go and/or print it out to file with your owner's manual and keep it in the trailer.
The receiver for your remote system is likely in the front passthrough, probably mounted on the top of the storage area so it's out of the way.
ADDED: You likely don't know the PIN. There are instructions on how to reset the pin on the last couple of pages of the PDF listed above. Choose one that you'll remember or be prepared to reset it every time you need to access the setup menu......