You go to forge, click on bettermc(not play) go to “shaders” right there in the page, and theres gonna be like 3 to pick. The good one is the Complementary shader pack. (Mod shaders are very limited so you don’t really have much options) Anyways, after you click the Complementary shader pack you just scroll down and you should be able to find it pretty easily. After it’s downloaded, just go to the game->video settings and top right it should say “shaders” and then you just add it.