Update README.md

README.md

@@ -20,7 +20,12 @@ For example if several streams must be created or not, If several inputs must be
 
 ## Dependency
 
-- [LSL4Unity](https://gitlab.inria.fr/openvibe/unity-games/LSL4Unity)
+### [LSL4Unity](https://gitlab.inria.fr/openvibe/unity-games/LSL4Unity)
+
+The LSL4Unity library used in this project is a fork with OpenViBE specifics.
+It is set as a submodule, so you need to pull it with the following command for the project to work:
+
+- git submodule update --init --recursive
 
 ## Screenshots