ESP8266 Pins: https://randomnerdtutorials.com/esp8266-pinout-reference-gpios/
Example Circuit Diagram Wemos D1 mini: https://escapequotes.net/wp-content/uploads/2016/02/2020-02-10_12-06-36.jpg
Guide to ESP8266https://tttapa.github.io/ESP8266/Chap01%20-%20ESP8266.html (Covers all aspects of ESP programming including OTA)