docs: Improving documentation for NLSR

Change-Id: Iada3c9bbc56b53fb66bfea1c99ef2204afaf9039
diff --git a/docs/INSTALL.rst b/docs/INSTALL.rst
index d99a3b9..d567598 100644
--- a/docs/INSTALL.rst
+++ b/docs/INSTALL.rst
@@ -12,7 +12,10 @@
 Refer to `Getting started with NFD <https://named-data.net/doc/NFD/current/INSTALL.html>`_
 for detailed installation and running instruction.
 
--  ChronoSync library
+-  ChronoSync library:
+
+Download the ChronoSync library and build it according to the instructions at the following
+address:
 
    ::