How to use network metrics tool

Not long ago Within my server, a player reported that Flashing characters. When I checked, I found that the frame rate dropped a lot. In the area where that player is standing

I use the NetGraph tool to check within the game. It turns out that the graph is very high (Million bit per second). I used the “network metrics” tool, found several “msgPackedClones”, I’m wondering where it came from. And I want to check to fix what happened?

Also, I want to know how to use network metrics tools. Where can I learn more?