diff --git a/docs/01-prerequisites.md b/docs/01-prerequisites.md
index a5bb8f2..7ca75e9 100644
--- a/docs/01-prerequisites.md
+++ b/docs/01-prerequisites.md
@@ -45,7 +45,7 @@ If you do change any of these, **please consider that a personal preference and
 
 The network used by the Virtual Box virtual machines is `192.168.56.0/24`.
 
-To change this, edit the [Vagrantfile](../vagrant/Vagrantfile) and set the new value for the network prefix at line 9. This should not overlap any of the other network settings.
+To change this, edit the [Vagrantfile](../vagrant/Vagrantfile) in your cloned copy (do not edit directly in github), and set the new value for the network prefix at line 9. This should not overlap any of the other network settings.
 
 Note that you do not need to edit any of the other scripts to make the above change. It is all managed by shell variable computations based on the assigned VM  IP  addresses and the values in the hosts file (also computed).