Cloning advice

README.md

@@ -1,6 +1,10 @@
 # Box2D-Lite
 A small 2D physics engine. Developed for the [2006 GDC Physics Tutorial](docs/GDC2006_Catto_Erin_PhysicsTutorial.pdf).
 
+# Cloning
+Box2D-Lite samples use [GLFW](https://www.glfw.org/) and [dear imgui](https://github.com/ocornut/imgui) as git submodules. Therefor, I recommend cloning box2d-lite using the following command:
+> git clone --recursive https://github.com/erincatto/box2d-lite.git
+
 # Building
 - Install [CMake](https://cmake.org/)
 - Ensure CMake is in the user `PATH`