Add more connecting text to the Development Environment chapter

By mentioning the next steps in various places, hopefully it will be
easier for developers to get everything set up.

Development_Environment.rst

@@ -5,14 +5,18 @@ Setting up a Development Environment
 
 This chapter describes how to set up an development environment for the
 Librem 5 phone that enables you to create, test, package and deploy
-applications. Development and testing can be performed using either the phone
-itself, a development kit or with an emulator that runs on a workstation.
+applications. Development and testing can be performed on the phone itself,
+using a development kit, or with an emulator that runs on a workstation.
 
 .. toctree::
-   :maxdepth: 2
+   :maxdepth: 1
 
    Development_Environment/Requirements.rst
    Development_Environment/Boards.rst
    Development_Environment/Boards/emulators.rst
    Development_Environment/Phone.rst
    Development_Environment/Workstation/index.rst
+
+It is useful to refer to the :ref:`requirements` section to check that you have
+everything you need to get started with development. The :ref:`workstation`
+section covers the tools that are commonly used to develop software.

Development_Environment/Boards/Troubleshooting.rst

@@ -3,8 +3,8 @@
 Troubleshooting
 ===============
 
-This page provides information for developers who need to investigate a problem
-with a development kit and want to diagnose it. It contains some useful
+This section provides information for developers who need to investigate a
+problem with a development kit and want to diagnose it. It contains some useful
 starting points for investigation and instructions for performing tasks that
 may be needed to help with testing.
 

Development_Environment/Requirements.rst

@@ -15,6 +15,12 @@ Applications can be tested on a :ref:`development board <boards>` such as the
 
  * If you are using the :ref:`imx8_devkit` then see the
    :ref:`imx8_devkit_package` section for an inventory of the package contents
-   and a list of items that may be useful.
+   and a list of items that may be useful. Set up the development board as
+   described on that page.
  * If you are using :ref:`qemu` then make sure you have enough RAM to be able
-   to run the emulation comfortably with your development workstation.
+   to run the emulation comfortably with your development workstation. Follow
+   the instructions on that page to set up an emulator with a test image.
+
+Once you have set up the development board or emulator, consult the
+:ref:`workstation` section of this chapter for information about the software
+you will need for application development.

Development_Environment/Workstation/Flatpak.rst

@@ -8,6 +8,9 @@ Applications for the phone will be distributed as flatpaks -- packages that can
 be distributed via repositories. Documentation for the ``flatpak`` tool and
 its ``flatpak-builder`` wrapper can be found in the `Flatpak documentation`_.
 
+Installing Flatpak Builder
+--------------------------
+
 Versions of these tools provided with modern GNU/Linux distributions should be
 sufficient. Debian-based distributions provide packages called ``flatpak`` and
 ``flatpak-builder`` that can be installed with the following command::
@@ -34,4 +37,19 @@ This package, or the equivalent on other platforms, is necessary if you want to
 build applications for the Librem 5 on systems with a processor architecture
 different to that used by the phone (aarch64).
 
+Installing Runtimes and SDKs for Development
+--------------------------------------------
+
+Flatpak uses specific :ref:`runtimes and SDKs <building_flatpaks_concepts>` for
+each target platform. The ones you will use depend on the technologies you will
+use to write applications for the Librem 5.
+
+ * If you are using GNOME-based applications, you will need to follow the steps
+   in :ref:`flatpak_setup_gnome`.
+ * If you are using Plasma-based applications based on KDE frameworks, you will
+   need to follow the steps in :ref:`flatpak_setup_plasma`.
+
+When you have installed a suitable runtime and SDK, you can start to develop
+your application and package it for testing on the phone or in an emulator.
+
 .. include:: /links.txt

Development_Environment/Workstation/index.rst

@@ -23,3 +23,6 @@ operating system. However, it may be necessary to install more up-to-date
 versions of some tools when new features are needed. The preferred method for
 doing this is to use Flatpak to install sandboxed versions of the required
 applications.
+
+Once you have set up the development tools for your workstation, you can start
+exploring :ref:`app_development` for the Librem 5.