diff --git a/README.md b/README.md
index e81d3fc..1113fde 100644
--- a/README.md
+++ b/README.md
@@ -18,4 +18,21 @@ Required Java Version
 ----
 JWebAssembly requires Java SE 8 or higher. It is tested with Java SE 8 on [travis-ci.org](https://travis-ci.org/i-net-software/jwebassembly).
 
+## Usage
 
+### Exporting functions
+To export a function to make it accessible from JavaScript you need add the annotation org.webassembly.annotation.Export
+
+```java
+import org.webassembly.annotation.Export;
+
+@Export
+public static int add( int a, int b ) {
+    return a + b;
+}
+```
+
+### Java Limits
+In version 1 of WebAssembly you can compile only:
+* static methods
+* use the data types int, long float and double