diff --git a/README.md b/README.md
index a2bc2c6..ce0ffa2 100644
--- a/README.md
+++ b/README.md
@@ -7,6 +7,17 @@ Photo ID template
 This repository contains an image template intended to help photographers to check whether or not a photography respects the dimensions for official documents.
 
 
+HOWTO
+-----
+
+1. Open the image template in your favorite image editor;
+2. open the photography you want to calibrate as a new layer;
+3. put the photography layer under the template;
+4. scale and center your photography;
+5. hide the template;
+6. export the result.
+
+
 References
 ----------
 
@@ -15,6 +26,7 @@ References
 - [Faces examples](http://www.correlance.com/cms/en/iso19794-5) (Correlance)
 - [Dépliant norme photo](http://www.diplomatie.gouv.fr/fr/IMG/pdf/depliant_norme_photo-2.pdf) (French government)
 
+
 License
 -------