I haven’t played it in a long while and I have been trying to help my younger brother get them working and I can’t figure it out for the life of me. I think he wants them on his game now since Pewdiepie is playing with them. I never used them myself so I don’t know if I need anything special to have them function or what.
what are you having trouble with exactly?
You install Optifine and then you download the shaders and move the zip files to the shader folder in .minecraft
If this doesn’t work, try different shader options because his PC might not be good enough to handle the better versions. Some require more powerful cards.
A few years back when I was playing the game (I mainly played creative and worked with Redstone) I noticed that the shaders, most of them in fact, require a beefy graphics card and CPU to run.
Like Khaos mentioned, you just have to put the shaders in the right folder after you have Optifine installed. I know that a lot of shaders do require Ray tracing abilities though.
I find them to be annoying myself. I was using one for a while. It is for lower-end PCs. If you want to try it, let me know. It is the best one I found for a basic shader but it just makes me dizzy.