diff --git a/documentation/ref-manual/introduction.xml b/documentation/ref-manual/introduction.xml
index 5db08a5a0e..bfec142f8c 100644
--- a/documentation/ref-manual/introduction.xml
+++ b/documentation/ref-manual/introduction.xml
@@ -266,25 +266,25 @@
                         Packages needed to build an image for a headless
                         system:
                         <literallayout class='monospaced'>
-     $ sudo yum -y install &CENTOS_HOST_PACKAGES_ESSENTIAL;
+     $ sudo yum install &CENTOS_HOST_PACKAGES_ESSENTIAL;
                         </literallayout></para></listitem>
                     <listitem><para><emphasis>Graphical Extras:</emphasis>
                         Packages recommended if the host system has graphics support:
                         <literallayout class='monospaced'>
-     $ sudo yum -y install SDL-devel xterm
+     $ sudo yum install SDL-devel xterm
                         </literallayout></para></listitem>
                     <listitem><para><emphasis>Documentation:</emphasis>
                         Packages needed if you are going to build out the
                         Yocto Project documentation manuals:
                         <literallayout class='monospaced'>
-     $ sudo yum -y install make docbook-style-dsssl docbook-style-xsl \
+     $ sudo yum install make docbook-style-dsssl docbook-style-xsl \
      docbook-dtds docbook-utils fop libxslt dblatex xmlto
                         </literallayout></para></listitem>
                     <listitem><para><emphasis>ADT Installer Extras:</emphasis>
                         Packages needed if you are going to be using the
                         <ulink url='&YOCTO_DOCS_ADT_URL;#using-the-adt-installer'>Application Development Toolkit (ADT) Installer</ulink>:
                         <literallayout class='monospaced'>
-     $ sudo yum -y install autoconf automake libtool glib2-devel
+     $ sudo yum install autoconf automake libtool glib2-devel
                         </literallayout></para></listitem>
                 </itemizedlist>
             </para>
@@ -301,7 +301,8 @@
             <itemizedlist>
                 <listitem><para>Git 1.7.5 or greater</para></listitem>
                 <listitem><para>tar 1.24 or greater</para></listitem>
-                <listitem><para>Python 2.7.3 or greater</para></listitem>
+                <listitem><para>Python 2.7.3 or greater not including
+                    Python 3.x, which is not supported.</para></listitem>
             </itemizedlist>
         </para>
 
@@ -312,8 +313,9 @@
             system.
             Regardless of the method, once you have the tarball you simply
             install it somewhere on you system, such as a directory in your
-            home directory, and then source the envirnoment script provided,
-            which adds the tools into <filename>PATH</filename>.
+            home directory, and then source the environment script provided,
+            which adds the tools into <filename>PATH</filename> and sets
+            any other environment variables required to run the tools.
             Doing so gives you working versions of Git, tar, Python and
             <filename>chrpath</filename>.
         </para>
@@ -335,7 +337,8 @@
                 or 64-bit system.
             </note>
             Once the build completes, you can find the file that installs the
-            the tools in <filename>tmp/deploy/sdk</filename> of the
+            the tools in the <filename>tmp/deploy/sdk</filename> subdirectory
+            of the
             <ulink url='&YOCTO_DOCS_DEV_URL;#build-directory'>Build Directory</ulink>.
             The file used to install the tarball has the string "buildtools"
             in the name.