diff --git a/Bootstrapping.md b/Bootstrapping.md
index baf2a14..95f56b3 100644
--- a/Bootstrapping.md
+++ b/Bootstrapping.md
@@ -4,7 +4,7 @@ To get the source code you need either of these:
 * wget + tar `wget --no-check-certificate "https://github.com/Araq/Nimrod/tarball/master"`
 * git `git clone git://github.com/Araq/Nimrod.git`
 
-After downloading the source (and extracting it), bootstrap with:
+After downloading the source (and extracting it), you need to extract build/csources.zip then you can bootstrap with:
 
 * `./build.sh` or `build.bat` (Windows)
 * `nimrod c koch`