diff --git a/doc/how_to_run.md b/doc/how_to_run.md
index 237dd68..9db0789 100644
--- a/doc/how_to_run.md
+++ b/doc/how_to_run.md
@@ -1,6 +1,12 @@
 How to run from the source tree
 ========
 
+Install [sbt](http://www.scala-sbt.org/index.html) at first.
+
+```
+$ brew install sbt
+```
+
 Run for Development
 --------