diff --git a/README.md b/README.md
index 4cd8ac97..9ebc08d7 100644
--- a/README.md
+++ b/README.md
@@ -10,4 +10,9 @@ series [Raytracing in One Weekend][weekend] which presents a raytracer
 in C++. I've adopted the programming style to suit the OCaml's
 functional style.
 
+## Usage
+
+You need to have OCaml installed. Running `make display` will compile
+the program and renders the hard-coded scene displayed above.
+
 [weekend]: http://in1weekend.blogspot.com/2016/01/ray-tracing-in-one-weekend.html