How to open Shaders configuration screen in Minecraft?

Before you get to that point, you have to find what looks to be a dingleberry and pull on it.

Alright, ill go from memory cause god its been so long. You'll need to pause and go into your shader settings. Towards the bottom right of the screen, you should see an "options" button. Here you will see some basic stuff for like anti-aliasing, and extra options.