docs: Update source installation instructions and other additions
Change-Id: Ie4976f728e0f091d829ba05539eb27c2e328e496
Refs: #1728
diff --git a/docs/FAQ.rst b/docs/FAQ.rst
index 084e443..146cbdc 100644
--- a/docs/FAQ.rst
+++ b/docs/FAQ.rst
@@ -281,3 +281,24 @@
For the list of available packages, refer to `NDN PPA repository`_ homepage.
.. _NDN PPA repository: https://launchpad.net/~named-data/+archive/ppa
+
+
+.. _How to start using NDN Overlay on Gentoo Linux:
+
+How to start using NDN Overlay on Gentoo Linux?
+-----------------------------------------------
+
+If you want to install NFD and other packages using Portage on Gentoo Linux, you can start
+using NDN Overlay.
+
+Simply checkout `NDN Overlay <https://github.com/Pesa/ndn-overlay>`_ repository to some
+location add the checkout path to ``PORTDIR_OVERLAY`` in ``/etc/portage/make.conf``:
+
+::
+
+ cd /some/path
+ git clone https://github.com/Pesa/ndn-overlay.git
+
+ # and then add /some/path/ndn-overlay to PORTDIR_OVERLAY in /etc/portage/make.conf
+
+Afterwards, you will be able to install ``nfd`` using standard mechanisms.