To install, just drop it into your Data folder for New Vegas.
Steam link:
C:\Program Files (x86)\Steam\SteamApps\common\Fallout New Vegas\Data

The Vault
---------

To find the vault, go to the lowest level of the solar tower - the level
with all of the protectrons and the elevator to the deck.
Go into the hallway with a single protectron in a stasis field, and go
down the hallway towards the dead end.
In the room on the right at the end of the hallway, there will be a manhole
behind a sandbag barricade and infront of an old table with an old terminal
and an advanced radiation suit. That's the entrance to the vault.


All credit for this mod goes to
Mharris22, Interplay and Black Isle Studios/Obsidian Entertainment