Okay, this step is different on every computers.
SO BE CAREFUL
READ
READ
READ THIS
COMPLETELY !!

Each ZIP contains 1 FOLDER
This folder is called "shaders"

How to install ? 

- Extract the ZIP
- Copy the "shaders" folder
- Go to your GTA folder
- Go to "common"
- You'll see the Shaders folder
- (OPTIONAL BUT RECOMMENDED) Rename the shaders folder in your GTA folder to something like "shadersbackup"
- Now copy your new shaders folder.

- To be sure you installed the shaders correctly :
  Your shaders folder should be near data & text folder 
  (YOURGTAFOLDER\common\shaders)

Now try;
If it crashes at start, use your backup or the backup I gave in the archive just in case

WHY SHOULD I INSTALL THIS SHADERS?:

They are made by P1CH3, it allows you to have less red-sky & better cutscenes (not all bright)
But just in case, instead of making them default (I know they can't work anywhere)
I made them optional.

Cheers!

Thanks to P1CH3 for the shaders :)