Update index.rst with new structure

Author: DennisClark

docs/index.rst

@@ -1,62 +1,105 @@
 ScanCode.io Documentation
 =========================
 
-Welcome! This is your starting point for everything ScanCode.io.
+ScanCode.io provides a Web UI and API to run and review complex scans in rich scripted
+pipelines, on different kinds of containers, docker images, package archives, manifests
+etc, to get information on licenses, copyrights, sources, and vulnerabilities.
 
-In this documentation, you’ll find:
+ScanCode.io provides an easy-to-use front-end to ScanCode Toolkit and other AboutCode
+projects.The flexible pipeline technology supports advanced scanning tasks such as
+container scanning and deploy-to-develop analysis. You can run ScanCode.io in a Docker
+container or install it on a Linux server. It provides full support for generating and
+consuming CycloneDX and SPDX SBOMs.
 
-- A **QuickStart guide** to run your first scan
-- An **overview** of what ScanCode.io is and what it can do
-- **Installation instructions** for full access
-- Step-by-step **tutorials** to dive deeper
-- In-depth **reference docs** on concepts, pipelines, configuration, and APIs
-- Guides on how to **contribute** to the project and community
+Documentation overview
+~~~~~~~~~~~~~~~~~~~~~~
 
-.. toctree::
-    :maxdepth: 2
-    :caption: Getting Started
+The overview below outlines how the documentation is structured
+to help you know where to look for certain things.
 
-    quickstart
-    introduction
-    installation
-    user-interface
-    faq
-    contributing
-    changelog
+.. rst-class:: clearfix row
 
-.. toctree::
-    :maxdepth: 2
-    :caption: Tutorials
-
-    tutorial_web_ui_analyze_docker_image
-    tutorial_web_ui_review_scan_results
-    tutorial_cli_analyze_docker_image
-    tutorial_cli_analyze_codebase
-    tutorial_api_analyze_package_archive
-    tutorial_license_policies
-    tutorial_vulnerablecode_integration
-    tutorial_web_ui_symbol_and_string_collection
-    tutorial_cli_end_to_end_scanning_to_dejacode
+.. rst-class:: column column2 top-left
+
+:ref:`getting-started`
+~~~~~~~~~~~~~~~~~~~~~~
+
+Start here if you are new to ScanCode.
+
+- :ref:`quickstart`
+
+ - :ref:`introduction`
+ - :ref:`installation`
+ - :ref:`user-interface`
+
+- :ref:`faq`
+
+.. rst-class:: column column2 top-right
+
+:ref:`tutorials`
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Learn via practical step-by-step guides.
+
+- :ref:`tutorial_web_ui_analyze_docker_image`
+- :ref:`tutorial_web_ui_review_scan_result`
+- :ref:`tutorial_cli_analyze_docker_image`
+- :ref:`tutorial_api_analyze_package_archive`
+- :ref:`tutorial_license_policies`
+- :ref:`tutorial_vulnerablecode_integration`
+- :ref:`tutorial_web_ui_symbol_and_string_collection`
+- :ref:`tutorial_cli_end_to_end_scanning_to_dejacode`
+
+.. rst-class:: column column2 bottom-left
+
+:ref:`how-to-guides`
+~~~~~~~~~~~~~~~~~~~~
+
+Helps you accomplish things.
+
+- :ref:`contributing`
+
+.. rst-class:: column column2 bottom-right
+
+:ref:`reference` and :ref:`explanation`
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Consult the reference to understand ScanCode.io concepts.
+
+- :ref:`scanpipe-concepts`
+- :ref:`built-in-pipelines`
+- :ref:`custom-pipelines`
+- :ref:`scanpipe-pipes`
+- :ref:`project-configuration`
+- :ref:`inputs`
+- :ref:`output-files`
+- :ref:`command-line-interface`
+- :ref:`rest-api`
+- :ref:`policies`
+- :ref:`data-models`
+- :ref:`automation`
+- :ref:`webhooks`
+- :ref:`application-settings`
+- :ref:`distros-os-images`
+
+.. rst-class:: row clearfix
+
+Improving Documentation
+~~~~~~~~~~~~~~~~~~~~~~~
+
+.. include::  /rst-snippets/improve-docs.rst
 
 .. toctree::
-    :maxdepth: 2
-    :caption: Reference
-
-    scanpipe-concepts
-    built-in-pipelines
-    custom-pipelines
-    scanpipe-pipes
-    project-configuration
-    inputs
-    output-files
-    command-line-interface
-    rest-api
-    policies
-    data-models
-    automation
-    webhooks
-    application-settings
-    distros-os-images
+   :maxdepth: 2
+   :hidden:
+
+   getting-started/index
+   tutorials/index
+   how-to-guides/index
+   reference/index
+   explanation/index
+
+   changelog
 
 Indices and tables
 ==================