After you exit the administrative office, you will have access to only two areas. The Officer's Barracks is one of them. If you need an item to obtain any note that you haven't found yet, simply continue following the storyline. The map below will give you a rough idea of the location of all 14 notes in this area, and the guide provides more detailed instructions on how to obtain them.
Note №1: Joubert's Last Diary
Once you enter the Officer's Barracks, go to the room with the sign "JOUBERT." The note will be lying on the table against the wall.
Note №2: Joubert's Journal - Strange Sounds
Inspect the same table and you will find the second note in the right drawer.
Note №3: Roman Tunnel Update
The next door along the corridor leads to the Strategic Operations Office. Upon entering the room, you will see a table with a note on one of its corners.
Note №4: Prisoner Under Guard
Find another table in the same office. It is located to the right of the entrance, next to the Monster's hole. The note can be found in its right drawer.
Note №5: Shooting at the Beast
Continue down the corridor and turn right. Enter the room with the sign "FOURNIER." Inside, there will be a table with a note.
Note №6: Enhanced Arsenal Security
The next note is in the left drawer of the same table.
Note №7: Speculations on Motive
The next door along the corridor leads to Reynard's office. You can open it using a grenade, brick, or weapon. There is a table against the opposite wall. You will find the note in its left drawer.
Note №8: Head of Security
Turn around and look at the door. To the right of it is a Cabinet with Documents. Inspect it to obtain the note.
Note №9: Digging Too Deep
Use bolt cutters to open a locked cabinet. Inside, you will find a note.
Note №10: Tussen's Fate
This note is located directly under the previous one.
Note №11: Report by Larue
This note is in Delisle's room. There are two ways to access it. You can either break the door or crawl through the ventilation shaft located in the Lounge room. Just move the barrels, grille, and boards to get inside. The note is on the table.
Note №12: Where Is Our Wine
Directly opposite the entrance to Delisle's room, there is a staircase. Descend it, and on the left, you will find another staircase leading to the wine cellar. At the end of it, the note will be on a box.
Note №13: Noyer's Translations
The door to the wine cellar is locked. You can unlock it with bolt cutters. Inside, near the door, there will be a cabinet. The note is in its lower compartment.
Note №14: List of Culprits
In the same cabinet, you will find the second note in the upper compartment.