Download the model.safetensors from this page and save it as t5_base.safetensors to your ComfyUI/models/clip/ directory.
Download the model.safetensors from this page and save it as stable_audio_open_1.0.safetensors to your ComfyUI/models/checkpoints/ directory.
The following flac audio file contains a workflow, you can download it and load it or drag it on the ComfyUI interface