diff --git a/doc/plugins.md b/doc/plugins.md
index bd24072..7d90392 100644
--- a/doc/plugins.md
+++ b/doc/plugins.md
@@ -11,6 +11,10 @@
 
 Also is hight recomendable to set the startup program on debug as the Sunfish.exe inside bin/debug folder.
 
+Create a class that inherits SunfishService and implement Process method.
+
+The call object contains methods for accessing request and response.
+
 # Use the plugin
 
 Place the plugin on the same path ans sunfish.exe