The most efficient way to download and install the ESP8266 platform is through the in the Arduino IDE. Installing - ESP8266 Arduino Core documentation
To get started with the ESP8266 in the Arduino environment, you don't just need a single "library"; you need the , which provides the necessary drivers and software framework to program these Wi-Fi chips as if they were standard Arduinos. How to Install the ESP8266 Arduino Core esp8266 library download arduino