How to program an ESP32 microcontroller from scratch, with all steps included. For my book on ASD, check out https://amzn.to/3Q0wKKb
The M5 Stick C Plus on Amazon: https://amzn.to/43vIQ0O
The board manager URL that I used was:
https://espressif.github.io/arduino-esp32/package_esp32_index.json