diff --git a/docs/from_the_sources.md b/docs/from_the_sources.md
index 156b290e3..79274c163 100644
--- a/docs/from_the_sources.md
+++ b/docs/from_the_sources.md
@@ -56,6 +56,7 @@ Once you have it, use `yarn`, as the non-root user owning the fetched code, to i
 
 ```
 $ yarn
+$ yarn build
 ```
 
 Then, you have to create a config file for `xo-server`:
@@ -89,6 +90,7 @@ First, we'll also install dependencies:
 
 ```
 $ yarn
+$ yarn build
 ```
 ## Running XO