How do I go about taking the sky from the shaderpack in the first picture and adding it to another shaderpack/datapack/resourcepack ?

Just like in the title, i was wondering if anyone had some quick tips or info on taking the Aoura and skybox from the shaderpack on the left (Astralex shaders 1.21.7) and adding it to BSL shaders or just adding it to a texturepack or something?