There is a ton of documentation, including several "getting started" guides here: IP Address Manager (IPAM) - Updated May 5, 2017
Here is a guide on troubleshooting and resolving IP address conflicts: IP Address Conflict – Resolve IP Address Conflict | SolarWinds
If you have a managed switch (most home switches are not managed, but just in case) you can log in and check the MAC Address Table to find out what port that MAC is seen on. Find one MAC for your conflicting IP, trace it through the network, take it offline, and either change the IP or start over and trace the other MAC to identify your other culprit. This may or may not be possible in your network equipment, but in case it is, I thought I'd suggest it.
I do my duplicate IP reporting through the syslog viewer. I have a rule setup that looks for IP-4-DUPADDR message. If found, it sends me an email with the details.
Have a read of this in regards to Solarwinds 'Find and Fix IP Conflicts".