Update download instructions.

README.md

@@ -67,6 +67,17 @@ with fs.open(files[0], "rb") as f:
     example_batch = xarray.load_dataset(f).compute()
 ```
 
+Alternatively, if you want a local copy, you can run this (downloaded files will not be re-downloaded unless instructed to otherwise):
+
+```python
+from huggingface_hub import hf_hub_download
+
+local_file: str = hf_hub_download(repo_id="shermansiu/dm_graphcast_datasets", filename=f"dataset/{files[0]}", repo_type="dataset")
+
+with open(local_file, "rb") as f:
+    example_batch = xarray.load_dataset(f).compute()
+```
+
 ## Citation
 - Paper: https://www.science.org/doi/10.1126/science.adi2336
 - Preprint: https://arxiv.org/abs/2212.12794