Conference Single DID user/moderater code into specific conference

I am attempting to modify our conference setup within freePBX to have the users and moderator dial a single DID and then enter a participant code. I have the IVR and the announcements. What I don’t want is the PIN announcement or the requirement for a PIN but wait for moderator. The way it needs to work is this:
User dials DID prompts for particpant code, they get MOH and Conf begin leader arrives announcement. Leader dials DID prompts for particpant code enters their Leader participant code then the conference is joined. I see an example of what we want:
setup a sperate extension that drops the user in the same conference. The marked user connects the conference.

exten => _682,1,Answer
exten => _682,2,Wait(1)
exten => _682,3,MeetMe(${EXTEN}|Msw)

exten => _682*,1,Answer
exten => _682*,2,Wait(1)
exten => _682*,3,Authenticate(1234)
exten => _682*,4,MeetMe(682|asMA)
(copied from this forum

However I am unsure as to how to accomplish this.

Any help is appreciated