docs: Document how to use the conversion script

Provide a detailed instruction on how to use the script

Author: TeddyHuang-00

src/timesfm_torch/README.md

@@ -1,9 +1,29 @@
 # Official Pytorch implementation of TimesFM
 
-TimesFM  (Time Series Foundation Model) is a pretrained time-series foundation model developed by Google
+TimesFM (Time Series Foundation Model) is a pretrained time-series foundation model developed by Google
 Research for time-series forecasting.
 
-* Paper: [A decoder-only foundation model for time-series forecasting](https://arxiv.org/abs/2310.10688), to appear in ICML 2024.
-* [Google Research blog](https://research.google/blog/a-decoder-only-foundation-model-for-time-series-forecasting/)
+- Paper: [A decoder-only foundation model for time-series forecasting](https://arxiv.org/abs/2310.10688), to appear in ICML 2024.
+- [Google Research blog](https://research.google/blog/a-decoder-only-foundation-model-for-time-series-forecasting/)
 
-## Stay tuned for all of the functionalities as that of the pax version. 
+---
+
+## Converting the model from pax to torch
+
+Before you start, make sure you are in the `timesfm` directory. If not, navigate to the `timesfm` directory. Do not forget to install the required specified in the `experiments/environment.yaml` or `experiments/environment_cpu.yaml`.
+
+1. Download the model checkpoint from the [official repository](https://huggingface.co/google/timesfm-1.0-200m) if you haven't already.
+   ```bash
+   git lfs install
+   git clone https://huggingface.co/google/timesfm-1.0-200m
+   ```
+2. Run the convertion script. You can specify the `model_path` and `output_path` as per your requirement. Here is an example (also the default values):
+   ```bash
+   # In `timesfm` directory
+   python3 -m src.timesfm_torch.convert_weights --model_path=timesfm-1.0-200m/checkpoints --output_path=ckpt/timesfm-1.0-200m.pth
+   ```
+3. The converted model will be saved in the `timesfm/ckpt/timesfm-1.0-200m.pth`.
+
+---
+
+## Stay tuned for all of the functionalities as that of the pax version.