Adding .json into arduino , for Mac ,

I am not able to add .json using preference,and if I check esp8266 in board manager, it is not available, also I am not able to install esp8266 file , which was created by esp8266 community , pls help , my os is Mac OS .

See the "Installing the Addon With the Arduino Boards Manager" section of:

Thanks for your suggestion,

actually i tired this, but i am getting the answer like this from arduino file signature verification failed. File ignored.


Earlier I was trying with Arduino version 1.6.9 which was latest and it didn't worked, Later I tried old version of Arduino 1.6.5 , it worked.......