New with questions

[Foreverfawn]

Ok, we are brand new to this forum but also to the world of RVing.

We have a 2015 Crossroads travel trailer. We are starting to get it ready for our first adventure.

I have this Question: If we are not connected to anything... electrical, etc. The lights work off of LP ? Or off the battery ? I think the refridgerator works off the LP ? However, I thought the outlets would work too. Am I wrong ? I want to be wrong... because than we don't have a problem. We have no electricity now.
One more question ? We just brought "Zoey" home a few weeks ago. Waiting for Spring. We have blinkers that work on the trailer. The driver's side brake light works. But the passenger side brake light doesn't work.

Any ideas what it could be ? Is there something we can check or do ?

Appreciate any advice.

Thanks !