Copy the content of the folder "We Happy Few - Reshade" to the game's installation folder.
Delete from [We Happy Few\GlimpseGame\Binaries\Win64] the folder "reshade-shaders" and the files "dxgi.dll", "dxgi.ini", "WE HAPPY FEW.ini", "dxgi.log".
Using the reshade preset:
The preset is enabled by default.
To disable or enable the preset press the Scroll Lock key.
In the case of We Happy Few, there is a problem that the preset is re-enabled automatically immediately after disabling it.