Update README_CN.md

python/examples/criteo_ctr_with_cube/README_CN.md

 ## 带稀疏参数索引服务的CTR预测服务
 (简体中文|[English](./README.md))
 
+### 编译源代码
+在本项目的根目录下，执行
+```
+mkdir build_server
+cd build_server
+cmake -DPYTHON_INCLUDE_DIR=$PYTHONROOT/include/python2.7/  -DPYTHON_LIBRARIES=$PYTHONROOT/lib/libpython2.7.so  -DPYTHON_EXECUTABLE=$PYTHONROOT/bin/python  -DCLIENT_ONLY=OFF ..
+make -j10
+make install -j10
+```
+
 ### 获取样例数据
+进入目录 `python/examples/criteo_ctr_with_cube`
 ```
 sh get_data.sh
 ```