I used 1 ambient sound:
- Empty Room: which is a sound effect of empty office/room available from Freesound.org. https://freesound.org/people/sons_pt/sounds/255522/
I also used 4 triggered sounds:
- Sound triggered by putting a pens holder on a table available from http://www.freesfx.co.uk/rx2/mp3s/6/18249_1464376495.mp3
- Sound triggered by stepping at the door, which is the door sliding sound. It's purchased from FreeSoundEffects.com. https://www.freesoundeffects.com/track/sliding-door-open-32293/sliding%20door/
- Sound triggered by colliding a chess piece available from http://freesound.org/people/anemicrose/sounds/94247/
- Sound of hallway noise triggered by getting closer to the corridor door. Available from http://freesound.org/people/PitStop100/sounds/66935/