I know ZERO about Hardware and IoT, but I would love to learn to tinker with these things like ESP32 and Arduinos, is this guide comprehensive and easy enough to follow to go from zero to building something?
Once setup, you can open any HA on a computer of your choice, plug in an esp* via usb, and flash it from your browser.
Once it's flashed over usb once, you can disconnect from your computer and flash it via OTA (i.e. remotely) in the future. You can connect whatever sensors or outputs you want and change it at any time.