https://huggingface.co/stabilityai/stable-cascade/tree/main
stage_b.safetensors and stage_c.safetensors (you can use the bf16 versions) go in ComfyUI/models/unet
stage_a.safetensors goes in ComfyUI/models/vae
and this: https://huggingface.co/stabilityai/stable-cascade/blob/main/text_encoder/model.safetensors goes in the ComfyUI/models/clip/ folder to be loaded with the Load CLIP node in the workflow
Note that OP posted this gist initially as a prototype, and a lot has changed since then. Your best path is going to be to start from his Stable Cascade examples. You'll notice that Stability AI released models with CLIP embedded, and other changes result in a simplified workflow.