The battery was being installed, and the connectors were placed backwards - now the car won't start, no power anywhere.
What is the extent of the damage, here? Am I lucky enough for this to be an easy fix, or do I need to take out a loan for repairs?

Thanks, D.

Check all under hood and under dash fuses with a test light or multimeter. Here's how to do it:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-46563-3.html#post252145

Yeah, probably just a main fuse in the underhood fusebox. It is held in with phillips screws. You can look at the fuse and tell if it is blown.