diff --git a/README.md b/README.md
index e1e39d9..c8610be 100644
--- a/README.md
+++ b/README.md
@@ -11,13 +11,18 @@ It is based on Google's [Blockly](https://developers.google.com/blockly/) and Ca
 - Android 7+ & Web-browser support. iOS support is upcoming!
 
 ## Development
-
 This is an Ionic 3 / Angular 5 application using Cordova Plugins for mobile-native functionality.
 
+
 ### dev env setup
 For a basic web version, only Node.js 8+ is required.
 For Android & iOS builds the respective platform tooling is required.
 
+This repo contains mandatory submodules; so you need to clone this repo via
+```sh
+git clone --recursive https://github.com/sensebox/blockly-app.git
+```
+
 To install npm dependencies run `npm install` once.
 
 Then run `npm start` to start a hot-reloading development view in the browser on <http://localhost:8100>.