You will definitely need these keys during the walkthrough, otherwise you will not able to escape from The Backrooms.

So, here all the keys that can be used in the game.

Movement:

W/Up - Move forward
S/Down - Move back
A/Left - Move left
D/Right - Move right
Left Shift - Run (Sprint)
Left Control (CTRL) - Press: Crouch, Hold: Lay down

Interface:

ESC - Pause

Gameplay Mechanics:

Left Mouse Button (LMB) - Zoom In
Right Mouse Button (RMB) - Zoom Out
F - Interact with Objects (Doors, Light Switches etc.)
Space-bar - Turn on the Flashlight

Thank you for attention and reading my guide!