Index: index.html
===================================================================
--- index.html	(revision 26556)
+++ index.html	(revision 26557)
@@ -10,8 +10,11 @@
 
 <p>
 <ul class="toc">
-	<li><a href="15_no_sch/index.html"> Designing a board from scratch</a>
-	<li><a href="16_tdx_netlist/index.html"> Importing a tedax netlist </a>
-	<li><a href="17_sch/index.html"> Designing from a schematic </a>
-	<li><a href="20_dbl_sided/index.html"> Double Sided </a>
+	<li><a href="15_no_sch/index.html"> 15. Designing a board from scratch</a>
+	<li><a href="16_tdx_netlist/index.html"> 16. Importing a tedax netlist </a>
+	<li><a href="17_sch/index.html"> 17. Designing from a schematic </a>
+	<li><a href="20_dbl_sided/index.html"> 20. Double Sided </a>
 </ul>
+
+The number in the tutorial title indicates the difficulty level of the
+tutorial.