You would set what extensions will ring usually into a ring group.This is done with tech level programming.But seeing as you undid this with touching 1 button you may have pressed an DND OR ? key.I think only a DND key would be capable of doing it with 1 touch.Do a Transfer 107 at the phone.That is what will show you what the function of each button is by dialing Transfer 107 and then press Volume Up to scroll through the 7 buttons.Make note of what each button has for the code.