I was sort of difficult for me to find these, so I thought I'd make a guide to help my fellow spiders out! This is my first guide, though, so it's kinda scuffed. But enjoy, I guess!
(Chapters are in order of how far away they are from the entrance.)

First, you need to be in the Office, obviously. The first note is hidden on the back of the PC, as shown here: (Hover over black rectangle to see image)
Make sure you remember or write down those numbers, because it seems to be random every time. (that's why these pictures won't line up, I took them in different iterations)
The second is in the bottom right corner of the board on the wall with all the sticky notes. Right here:
Finally, the third note is near the desk in the far right corner (looking at the room from the vent you enter from) above a notebook. This is what it looks like:
You should have all the digits now.

It's pretty simple here on out. Just take all the digits you've collected and put them in in the right order on the safe by clicking the buttons with your web. The screen should flash green. Turn the knob, and see your treasure. No, wait image the treasures. Gold, expensive shoes,good food... nah. It's just a buncha rubber duckies. But that's even better!

Now you too shall share this glorious treasure! I'd like it if you did the thing with the badges, too. Not really sure how it works tbh

Best wishes,
port4d, avid spider-er