Thanks for sharing this information here, crucian4! It's very kind of you to help out.
renecyberdoc - If you'd like to read some additional information about The Summit, we have a dedicated article about it here. In terms of accessing the mode once you meet the conditions posted above:
To gain access to The Summit, players can fast travel to the location from the New York City main map or speak to the Pilot outside of the White House Base of Operations.