Update READMEs to fix numbering and add git clone [(#1464)](GoogleCloudPlatform/python-docs-samples#1464)

Author: frankyn

samples/snippets/api/README.rst

@@ -32,10 +32,16 @@ credentials for applications.
 Install Dependencies
 ++++++++++++++++++++
 
+#. Clone python-docs-samples and change directory to the sample directory you want to use.
+
+    .. code-block:: bash
+
+        $ git clone https://github.com/GoogleCloudPlatform/python-docs-samples.git
+
 #. Install `pip`_ and `virtualenv`_ if you do not already have them. You may want to refer to the `Python Development Environment Setup Guide`_ for Google Cloud Platform for instructions.
 
- .. _Python Development Environment Setup Guide:
-     https://cloud.google.com/python/setup
+   .. _Python Development Environment Setup Guide:
+       https://cloud.google.com/python/setup
 
 #. Create a virtualenv. Samples are compatible with Python 2.7 and 3.4+.