no Additional Boards Manager URLs

I'm using 1.7.11 Under File- Preferences "Additional Boards Manager URLs" doesn't appear, so I'm unable to set up my Adafruit board. Any help would be appreciated

You are on the wrong Arduino site...try arduino.org just for now until they get merged..

Or use the IDE from here 1.6.12 which has a board manager but you will want to uninstall the other one completely first.