diff --git a/README.md b/README.md
index 9636b78..438257d 100644
--- a/README.md
+++ b/README.md
@@ -1 +1,7 @@
 I'm learning Chinese, so I'm doing it with the help of Matrix, too.
+
+Each HTML file is freely portable among machines because all images and sounds are embedded. Take those files anywhere you like.
+
+Table of contents:
+
+* 01.Cellular.html