Added links to manual.

download.html

@@ -52,6 +52,8 @@
 
           <p>Briar for Android is currently in <a href="news/2017-beta-released-security-audit.html">public beta</a> and is available for download <a href="https://play.google.com/store/apps/details?id=org.briarproject.briar.beta">from Google Play</a>.</p>
 
+          <p>The <a href="https://briarproject.org/manual">manual</a> describes how to use Briar and the features that are available.</p>
+
           <p>If you'd like to be informed when the final app is available, please <a href="https://lists.sourceforge.net/lists/listinfo/briar-announce">join the announcement mailing list</a>.</p>
 
           <p>If you're interested in getting involved or following the progress of the project, please <a href="https://lists.sourceforge.net/lists/listinfo/briar-devel">join the development mailing list</a> or email <a href="mailto:contact@briarproject.org">contact@briarproject.org</a> [<a href="keys/contact.asc">PGP key</a>].</p>

how-it-works.html

@@ -59,6 +59,8 @@ messages are synchronized directly between the users' devices.
 If the internet's down, Briar can sync via Bluetooth or Wi-Fi, keeping the information flowing in a crisis.
 If the internet's up, Briar can sync via the Tor network, protecting users and their relationships from surveillance.</p>
 
+         <p>The <a href="https://briarproject.org/manual">manual</a> describes how to use Briar and the features that are available.</p>
+
           <figure>
             <img src="img/diagram_secure.png" class="" alt="Briar"/>
             <figcaption>Briar uses direct, encrypted connections between users to