Open File
menu > Preferences
.
On Additional Boards Manager URLs
paste this link:
https://arduino.esp8266.com/stable/package_esp8266com_index.json
Open Tools
menu > Board
> Board Manager
.
Install version 2.7.4
of library esp8266
by Esp8266 Community.
Open Tools
menu > Board
> ESP8266 Boards
.
Select NodeMCU 1.0 (ESP-12E Module)
.
Open Sketch
menu > Include Library
> Manage Libraries
.
Find and install:
- Firebase ESP8266 Client (3.3.7) by Mobizt
- ArduinoJson (5.13.1) by Benoit Blanchon