Setup ESP8266 feather for Arduino IDE 1. In Arduino IDE, got to Boards Manager and add this URL. Go to Additional Boards Manager URL textbox. Copy & paste this URL into the texbox.: http://arduino.esp8266.com/stable/package_esp8266com_index.json Click OK. Separate URLS with a comma if there are more than one. 2. Close and restart Arduino IDE 3. Go to Tools | Board Manager in the Arduino IDE. Scroll for your board ESP8266 and click INSTALL button. 4. Close Board Manager. 5. Plug in your board. 6. In your new sketch you can choose Tools | Select your board and the COM port (USB port #) 7. Find your Com port: Press WindowKey + X at the same time to bring up menu. Choose Device Manager. Expand the Ports (COM) section and look for Silicon Labs UART Bridge (COM#). Make a note of this COM port# so you can use it in your code.