[minor] add a windows installation guide

docs/setup_windows.md

+# Nunchaku Setup Guide (Windows)
+
+# Environment Setup
+
+## 1. Install Cuda
+
+Download and install the latest CUDA Toolkit from the official [NVIDIA CUDA Downloads](https://developer.nvidia.com/cuda-downloads?target_os=Windows&target_arch=x86_64&target_version=Server2022&target_type=exe_local). After installation, verify the installation:
+
+```bash
+nvcc --version
+```
+
+## 2. Install Visual Studio C++ Build Tools
+
+Download from the official [Visual Studio Build Tools page](https://visualstudio.microsoft.com/visual-cpp-build-tools/). During installation, select the following workloads:
+
+- **Desktop development with C++**
+- **C++ tools for Linux development**
+
+### 3. Git
+
+Download Git from [https://git-scm.com/downloads/win](https://git-scm.com/downloads/win) and follow the installation steps.
+
+## 4. (Optional) Install Conda
+
+Conda helps manage Python environments. You can install either Anaconda or Miniconda from the [official site](https://www.anaconda.com/download/success).
+
+## 5. (Optional) Installing ComfyUI
+
+You may have some various ways to install ComfyUI. For example, I used ComfyUI CLI. Once Python is installed, you can install ComfyUI via the CLI:
+
+```shell
+pip install comfy-cli
+comfy-cli install
+```
+
+To launch ComfyUI:
+
+```shell
+comfy-cli launch
+```
+
+# Installing Nunchaku
+
+## Step 1: Identify Your Python Environment
+
+To ensure correct installation, you need to find the Python interpreter used by ComfyUI. Launch ComfyUI and look for this line in the log:
+
+```bash
+** Python executable: G:\ComfyuI\python\python.exe
+```
+
+Then verify the Python version and installed PyTorch version:
+
+```bash
+"G:\ComfyuI\python\python.exe" --version
+"G:\ComfyuI\python\python.exe" -m pip show torch
+```
+
+## Step 2: Install PyTorch (≥2.5) if you haven’t
+
+Install PyTorch appropriate for your setup
+
+- **For most users**:
+  
+    ```bash
+    "G:\ComfyuI\python\python.exe" -m pip install torch==2.6 torchvision==0.21 torchaudio==2.6
+    ```
+    
+- **For RTX 50-series GPUs** (requires PyTorch ≥2.7 with CUDA 12.8):
+  
+    ```bash
+    "G:\ComfyuI\python\python.exe" -m pip install --pre torch torchvision torchaudio --index-url https://download.pytorch.org/whl/nightly/cu128
+    ```
+    
+
+## Step 3: Install Nunchaku
+
+### Prebuilt Wheels
+
+You can install Nunchaku wheels from one of the following:
+
+- [Hugging Face](https://huggingface.co/mit-han-lab/nunchaku/tree/main)
+- [ModelScope](https://modelscope.cn/models/Lmxyy1999/nunchaku)
+- [GitHub Releases](https://github.com/mit-han-lab/nunchaku/releases)
+
+Example (for Python 3.10 + PyTorch 2.6):
+
+```bash
+"G:\ComfyuI\python\python.exe" -m pip install https://huggingface.co/mit-han-lab/nunchaku/resolve/main/nunchaku-0.2.0+torch2.6-cp310-cp310-win_amd64.whl
+```
+
+To verify the installation:
+
+```bash
+"G:\ComfyuI\python\python.exe" -c "import nunchaku"
+```
+
+You can also run a test (requires a Hugging Face token for downloading the models):
+
+```bash
+"G:\ComfyuI\python\python.exe" -m huggingface-cli login
+"G:\ComfyuI\python\python.exe" -m nunchaku.test
+```
+
+### (Alternative) Build Nunchaku from Source
+
+Please use CMD instead of PowerShell for building.
+
+- Step 1: Install Build Tools
+  
+    ```bash
+    C:\Users\muyang\miniconda3\envs\comfyui\python.exe
+    "G:\ComfyuI\python\python.exe" -m pip install ninja setuptools wheel build
+    ```
+    
+- Step 2: Clone the Repository
+  
+    ```bash
+    git clone https://github.com/mit-han-lab/nunchaku.git
+    cd nunchaku
+    git submodule init
+    git submodule update
+    ```
+    
+- Step 3: Set Up Visual Studio Environment
+  
+    Locate the `VsDevCmd.bat` script on your system. Example path:
+    
+    ```
+    C:\Program Files (x86)\Microsoft Visual Studio\2022\BuildTools\Common7\Tools\VsDevCmd.bat
+    ```
+    
+    Then run:
+    
+    ```bash
+    "C:\Program Files (x86)\Microsoft Visual Studio\2022\BuildTools\Common7\Tools\VsDevCmd.bat" -startdir=none -arch=x64 -host_arch=x64
+    set DISTUTILS_USE_SDK=1
+    ```
+    
+- Step 4: Build Nunchaku
+  
+    ```bash
+    "G:\ComfyuI\python\python.exe" setup.py develop
+    ```
+    
+    Verify with:
+    
+    ```bash
+    "G:\ComfyuI\python\python.exe" -c "import nunchaku"
+    ```
+    
+    You can also run a test (requires a Hugging Face token for downloading the models):
+    
+    ```bash
+    "G:\ComfyuI\python\python.exe" -m huggingface-cli login
+    "G:\ComfyuI\python\python.exe" -m nunchaku.test
+    ```
+    
+
+# Use Nunchaku in ComfyUI
+
+## 1. Install the Plugin
+
+Clone the [ComfyUI-Nunchaku](https://github.com/mit-han-lab/ComfyUI-nunchaku) plugin into the `custom_nodes` folder:
+
+```
+cd ComfyUI/custom_nodes
+git clone https://github.com/mit-han-lab/ComfyUI-nunchaku.git
+```
+
+Alternatively, install using [ComfyUI-Manager](https://github.com/Comfy-Org/ComfyUI-Manager) or `comfy-cli`.
+
+## 2. Download Models
+
+- **Standard FLUX.1-dev Models**
+  
+    Start by downloading the standard [FLUX.1-dev text encoders](https://huggingface.co/comfyanonymous/flux_text_encoders/tree/main) and [VAE](https://huggingface.co/black-forest-labs/FLUX.1-dev/blob/main/ae.safetensors). You can also optionally download the original [BF16 FLUX.1-dev](https://huggingface.co/black-forest-labs/FLUX.1-dev/blob/main/flux1-dev.safetensors) model. An example command:
+    
+    ```bash
+    huggingface-cli download comfyanonymous/flux_text_encoders clip_l.safetensors --local-dir models/text_encoders
+    huggingface-cli download comfyanonymous/flux_text_encoders t5xxl_fp16.safetensors --local-dir models/text_encoders
+    huggingface-cli download black-forest-labs/FLUX.1-schnell ae.safetensors --local-dir models/vae
+    huggingface-cli download black-forest-labs/FLUX.1-dev flux1-dev.safetensors --local-dir models/diffusion_models
+    ```
+    
+- **SVDQuant 4-bit FLUX.1-dev Models**
+  
+    Next, download the SVDQuant 4-bit models:
+    
+    - For **50-series GPUs**, use the [FP4 model](https://huggingface.co/mit-han-lab/svdq-fp4-flux.1-dev).
+    - For **other GPUs**, use the [INT4 model](https://huggingface.co/mit-han-lab/svdq-int4-flux.1-dev).
+    
+    Make sure to place the **entire downloaded folder** into `models/diffusion_models`. For example:
+    
+    ```bash
+    huggingface-cli download mit-han-lab/svdq-int4-flux.1-dev --local-dir models/diffusion_models/svdq-int4-flux.1-dev
+    ```
+    
+- **(Optional): Download Sample LoRAs**
+  
+    You can test with some sample LoRAs like [FLUX.1-Turbo](https://huggingface.co/alimama-creative/FLUX.1-Turbo-Alpha/blob/main/diffusion_pytorch_model.safetensors) and [Ghibsky](https://huggingface.co/aleksa-codes/flux-ghibsky-illustration/blob/main/lora.safetensors). Place these files in the `models/loras` directory:
+    
+    ```bash
+    huggingface-cli download alimama-creative/FLUX.1-Turbo-Alpha diffusion_pytorch_model.safetensors --local-dir models/loras
+    huggingface-cli download aleksa-codes/flux-ghibsky-illustration lora.safetensors --local-dir models/loras
+    ```
+    
+
+## 3. Set Up Workflows
+
+To use the official workflows, download them from the [ComfyUI-nunchaku repository](https://github.com/mit-han-lab/ComfyUI-nunchaku/tree/main/workflows) and place them in your `ComfyUI/user/default/workflows` directory. The command can be 
+
+```bash
+# From the root of your ComfyUI folder
+cp -r custom_nodes/ComfyUI-nunchaku/workflows user/default/workflows/nunchaku_examples
+```
+
+You can now launch ComfyUI and try running the example workflows.
+
+# Troubleshooting
+
+If you encounter issues, refer to our:
+
+- [FAQs](https://github.com/mit-han-lab/nunchaku/discussions/262)
+- [GitHub Issues](https://github.com/mit-han-lab/nunchaku/issues)
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