docs: rearrange README.rst to include a short code sample (#1812)

* docs: rearrange README.rst to include a short code sample

Towards internal issue 424443170

* change to BigFrames

Author: tswast

README.rst

@@ -1,16 +1,60 @@
-BigQuery DataFrames
-===================
+BigQuery DataFrames (BigFrames)
+===============================
 
 |GA| |pypi| |versions|
 
-BigQuery DataFrames provides a Pythonic DataFrame and machine learning (ML) API
-powered by the BigQuery engine.
+BigQuery DataFrames (also known as BigFrames) provides a Pythonic DataFrame
+and machine learning (ML) API powered by the BigQuery engine.
 
 * ``bigframes.pandas`` provides a pandas-compatible API for analytics.
 * ``bigframes.ml`` provides a scikit-learn-like API for ML.
 
-BigQuery DataFrames is an open-source package. You can run
-``pip install --upgrade bigframes`` to install the latest version.
+BigQuery DataFrames is an open-source package.
+
+**Version 2.0 introduces breaking changes for improved security and performance. See below for details.**
+
+Getting started with BigQuery DataFrames
+----------------------------------------
+
+The easiest way to get started is to try the
+`BigFrames quickstart <https://cloud.google.com/bigquery/docs/dataframes-quickstart>`_
+in a `notebook in BigQuery Studio <https://cloud.google.com/bigquery/docs/notebooks-introduction>`_.
+
+To use BigFrames in your local development environment,
+
+1. Run ``pip install --upgrade bigframes`` to install the latest version.
+
+2. Setup `Application default credentials <https://cloud.google.com/docs/authentication/set-up-adc-local-dev-environment>`_
+   for your local development environment enviroment.
+
+3. Create a `GCP project with the BigQuery API enabled <https://cloud.google.com/bigquery/docs/sandbox>`_.
+
+4. Use the ``bigframes`` package to query data.
+
+.. code-block:: python
+
+    import bigframes.pandas as bpd
+
+    bpd.options.bigquery.project = your_gcp_project_id
+    df = bpd.read_gbq("bigquery-public-data.usa_names.usa_1910_2013")
+    print(
+        df.groupby("name")
+        .agg({"number": "sum"})
+        .sort_values("number", ascending=False)
+        .head(10)
+        .to_pandas()
+    )
+
+
+Documentation
+-------------
+
+To learn more about BigQuery DataFrames, visit these pages
+
+* `Introduction to BigQuery DataFrames (BigFrames) <https://cloud.google.com/bigquery/docs/bigquery-dataframes-introduction>`_
+* `Sample notebooks <https://github.com/googleapis/python-bigquery-dataframes/tree/main/notebooks>`_
+* `API reference <https://cloud.google.com/python/docs/reference/bigframes/latest/summary_overview>`_
+* `Source code (GitHub) <https://github.com/googleapis/python-bigquery-dataframes>`_
 
 ⚠️ Warning: Breaking Changes in BigQuery DataFrames v2.0
 --------------------------------------------------------
@@ -44,22 +88,6 @@ To learn about these changes and how to migrate to version 2.0, see the
 .. |versions| image:: https://img.shields.io/pypi/pyversions/bigframes.svg
    :target: https://pypi.org/project/bigframes/
 
-Documentation
--------------
-
-* `BigQuery DataFrames source code (GitHub) <https://github.com/googleapis/python-bigquery-dataframes>`_
-* `BigQuery DataFrames sample notebooks <https://github.com/googleapis/python-bigquery-dataframes/tree/main/notebooks>`_
-* `BigQuery DataFrames API reference <https://cloud.google.com/python/docs/reference/bigframes/latest/summary_overview>`_
-* `BigQuery DataFrames supported pandas APIs <https://cloud.google.com/python/docs/reference/bigframes/latest/supported_pandas_apis>`_
-
-
-Getting started with BigQuery DataFrames
-----------------------------------------
-Read `Introduction to BigQuery DataFrames <https://cloud.google.com/bigquery/docs/bigquery-dataframes-introduction>`_
-and try the `BigQuery DataFrames quickstart <https://cloud.google.com/bigquery/docs/dataframes-quickstart>`_
-to get up and running in just a few minutes.
-
-
 License
 -------