Update README.md

README.md

@@ -13,12 +13,13 @@ this step will generate a dist directory under frontend
 
 ### Step 2: copy frontend/dist to server/visualdl/frontend/dist
 ```shell
-cp -r frontend/dist server/visualdl/frontend/
+mkdir -p server/visualdl/frontend/dist
+cp -r frontend/dist server/visualdl/frontend/dist
 ```
 
 #### Step 3: build and install Python package
 ```shell
-cd server/visualdl
+cd server/
 python setup.py bdist_wheel
 cd dist
 pip install --upgrade visualdl-0.0.1-py2-none-any.whl