Grafana is the most essential application in my job. I can use Notepad to code in a world without IDEs. I couldn't keep a damn thing running in the real world without Grafana. And I've been forced against my will to use alternatives in the past.
Basically brute force, I'm not great with it but I was the one on my team responsible for setting up our dashboards. I wrote the prometheus metric collection in our microservices and built the dashboards from that data.
There are tons of free dashboards though for monitoring resources and such so a lot of things I use are just downloaded from the Grafana website. And the docs are good too. So looking at examples + documentation is how I learn. It would be helpful if I was better with math though.