Move root ReadMe env setting up to training

Author: JacoCheung

examples/hstu/training/README.md

@@ -3,12 +3,14 @@ We have supported both retrieval and ranking model whose backbones are HSTU laye
 ## Environment Setup
 ### Start from dockerfile
 
-We provide [dockerfile](./docker/Dockerfile) for users to build environment. 
+We provide [dockerfile](../../../docker/Dockerfile) for users to build environment. 
 ```
+git clone https://github.com/NVIDIA/recsys-examples.git && cd recsys-examples
 docker build -f docker/Dockerfile --platform linux/amd64 -t recsys-examples:latest .
 ```
 If you want to build image for Grace, you can use 
 ```
+git clone https://github.com/NVIDIA/recsys-examples.git && cd recsys-examples
 docker build -f docker/Dockerfile --platform linux/arm64 -t recsys-examples:latest .
 ```
 You can also set your own base image with args `--build-arg <BASE_IMAGE>`.