On this page of the solution Fallout 76 Wastelanders, discover the complete progress of the Buried Treasure Main Quest.
Return to the mysterious cave to find your team (pictures1and2). After the discussion, ask Lou to blow up the door of the shelter (picture3).
Before entering the shelter, talk to Meg who warns you about Johnny (picture4). Follow Johnny into the shelter (picture5).
Use the terminal to try to open the door (pictures6and7), then pick up the nearby access card (picture8).
Use the access card on the reader to open the door (picture9), and activate the circuit breaker (picture10).
Follow your team and eliminate all the robots (picture11). Then use the intercom to chat with your team (picture12). Let Gail hack into the scanner and speak with the members of security.
Pass the security gate (picture13) and progress in the corridor by eliminating the robots (picture14), until you reach the atrium (picture15).
Get rid of all the robots and ask Ra-Ra to open the door (picture16). Resume your progress towards the operations center and ask Ra-Ra to open another door to reach the Perforator unique weapon (pictures17and18).
Finally, go through the door at the end of the corridor to end this main quest (picture19).