This small and simple guide will help you quickly complete the “Hiding in plain sight” achievement”
First is located under the window next to the computer
The second one is located behind the monitor
The third one is under the shelf that is closest to the entrance
The fourth is in a small room under the electrical panel
The fifth one is under the stairs
The sixth is behind the ventilation system which is under the stairs
The seventh is located under the shelf where the palettes are located
The eighth is on a fan under the ceiling
The ninth is next to this fan on the hood
For the next two, it is necessary to unblock the premises with parcels
The tenth is pasted behind the monitor
The eleventh one is in the trash on the gate on the back side
Thanks to VeeXell for his great guide, all credit to his effort. you can also read the original guide from Steam Community. enjoy the game.