UPS Monitoring project

So I have barely used Linux before and have never used Nagios before. A few weeks ago I was tasked with a project to monitor a handful of UPS’s. I know Nagios can do this, but I have no idea how. I know you need to edit the config file, but I’m not sure how to. I know there are a variety of plug-ins for APC UPS monitoring, but I have no clue on how to use them. I’ve read just about every webpage regarding this, but each one assumes the reader knows what he/she is doing, and I do not lol. Any help is greatly appreciated