diff --git a/code/pre_processing/README.md b/code/pre_processing/README.md
index 9b01c32..09bb44d 100644
--- a/code/pre_processing/README.md
+++ b/code/pre_processing/README.md
@@ -75,5 +75,6 @@ https://github.com/guohaoxiang/NH-Rep/blob/42ae22bf8fc3f1b4f9f5592443c29aafe8690
 
 After that, rebuild the executable files, and re-run 'python gen_training_data_yaml.py' and 'python gen_training_data_yaml.py -r'. There will be generated training data in _training_data_repair_.
 
-docker run -it --name brep_processor -v ~/NH-Rep/code/pre_processing:/app brep_pre_processing:v1
 
+docker build -t brep_pre_processing:v1 .
+docker run -it --name brep_processor -v ~/NH-Rep/code/pre_processing:/app brep_pre_processing:v1