EmonCMS.org for simple EV charging

I had setup EmonCMS to collect info of my OpenEVSE car charger using this guide
https://docs.openenergymonitor.org/emonevse/setup.html#emoncms-setup
I got it to work but I am very confused, do we need all these data or just some?
looks like the graph is only using power and energy


do I need all these other inputs?

EmonCMS.org fees are based on amount of info being sent. (update I just saw page saying fee based on feeds, so not inputs?)

I couldn’t find any simple how to or videos explaining or it was too complex that it confused me, I don’t have solar or anything else yet. I just want to track how much power the car charger is using.
I need a simple how to on something basic and then add more in steps to learn little at a time without getting overwhelmed.

is EmonCMS pulling info via API or is the OpenEVSE pushing info?
Feeds are what is available to display and for graphs to use?