1) Download ReShade from http://reshade.me/
2) Open ReShade setup and click 'Select game'.
3) Here you must select the correct '.exe' file inside the game installation directory. There are two of them, one for 32-bit and the other for 64-bit (located in the x64 folder). Select the one you are using to play.
4) The ReShade setup will now ask you to select the rendering API. If you selected the 64-bit file in the previous step, choose 'Direct3D 10+'. If you selected the 32-bit file, choose 'Direct3D 8/9'.
5) You should be prompted to download a 'collection of standard effects'. Click 'Yes'.
6) After the download is completed, you can select which effect to install. You can choose only the effects 'Clarity', 'Curves', 'LumaSharpen' and 'Tonemap', or just install all of them (these four are the only required)
. Click OK and close the ReShade setup.
7) Get the '.ini' file from the preset and put it in the same folder that you installed ReShade (same folder as the '.exe' file).
8) Open the game, the shaders should be loaded. Hit Shift+F2 to open the ReShade overlay.
9) In the overlay, click 'Continue'. The next step is the preset selection, choose the 'Bleak.ini' file from the red combobox and hit 'Continue' and 'Continue' again and then 'Finish'. Hit Shift+F2 again to close the overlay, the installation is done.
If you want to tweak some settings simply hit Shift+F2 to open/close the ReShade overlay. I personally set the scroll-lock key to toggle the effect in-game.