docs: add installation guide for git lfs on various platforms

Add detailed instructions for installing git lfs on Linux, macOS, and Windows
to facilitate users in downloading models from ModelScope repository. The guide
is included in the `how_to_download_models_zh_cn.md` document.

docs/how_to_download_models_zh_cn.md

@@ -33,6 +33,22 @@ model_dir = snapshot_download('wanderkid/PDF-Extract-Kit')
 #### Git下载
 也可以使用git clone从 ModelScope 下载模型:
 
+需要先安装git lfs
+
+>##### On Linux
+>
+>Debian and RPM packages are available from packagecloud, see the [Linux installation instructions](INSTALLING.md).
+>
+>##### On macOS
+>
+>[Homebrew](https://brew.sh) bottles are distributed and can be installed via `brew install git-lfs`.
+>
+>##### On Windows
+>
+>Git LFS is included in the distribution of [Git for Windows](https://gitforwindows.org/).
+>Alternatively, you can install a recent version of Git LFS from the [Chocolatey](https://chocolatey.org/) package manager.
+
+然后通过git clone下载模型:
 ```bash
 git clone https://www.modelscope.cn/wanderkid/PDF-Extract-Kit.git
 ```