Network troubleshooting tutorial

I was hoping someone might be able to point me to a source that would help me learn about network troubleshooting. I do a lot of tinkering at home and have really very limited knowledge of how things really work. I am running PfSense and would love to be more adept at figuring out issues.

Understanding the OSI model is helpful for troubleshooting. If you start at the bottom and work your way up until you find which layer your problems are starting at then you can narrow down the problem. If it’s a layer 2 problem it’s probably the switch, layer 3 probably the router, layer 4 probably the firewall etc.