diff --git a/docs/chu3-national-matching.md b/docs/chu3-national-matching.md
index c33cef77..a36a828e 100644
--- a/docs/chu3-national-matching.md
+++ b/docs/chu3-national-matching.md
@@ -31,6 +31,7 @@ This is tested on Chusan 2.27.
 ### Firewall Rules
 
 Below is a simple command to add firewall rules for Chunithm.
+(Put this into a text file and change the file extension to .bat)
 
 ```shell
 @echo off