Added plugin installation, edited text file export details

Author: splorp

readme.md

@@ -4,7 +4,7 @@ Export [Kirby](https://getkirby.com/) content for use with the [Paperback Book M
 
 ## What does this plugin do?
 
-The plugin generates a lightly formatted plain text file from a set of pages specified by the user.
+The plugin generates a lightly formatted plain text file from a set of pages specified by the user. The text file is used to create a “book” package which can be viewed on a Newton OS device.
 
 An example of this file can be downloaded using the following link. The file contains all of the terms currently published on the [Newton Glossary](http://newtonglossary.com/) site.
 
@@ -14,9 +14,46 @@ An example of this file can be downloaded using the following link. The file con
 
 Paperback is a simple cross-platform utility created by [David Fedor](http://thefedors.com/pobox/) that takes plain text files and quickly packages them for viewing on a Newton OS device. Since the Paperback utility only runs under classic Mac OS and Windows, an online [Paperback Book Maker](https://ritsuko.chuma.org/paperback/) was developed by [Victor Rehorst](https://github.com/chuma) for all your cross-platform needs.
 
+## Installation
+
+After installing the plugin using one of the methods listed below, visiting `yoursite.com/export/paperback` should automatically download a text file without any additional configuration.
+
+### Download
+
+To install the plugin manually, [download the files](https://github.com/splorp/kirby-paperback-export/archive/master.zip) and put them in:
+
+`site/plugins/paperback-export`
+
+### Kirby CLI
+
+Installing the plugin using the Kirby [command line interface](https://github.com/getkirby/cli):
+
+    $ kirby plugin:install splorp/kirby-paperback-export
+
+Updating the plugin using the Kirby CLI:
+
+    $ kirby plugin:update splorp/kirby-paperback-export
+
+### Git Submodule
+
+Installing the plugin as a Git submodule:
+
+    $ cd your/project/root
+    $ git submodule add https://github.com/splorp/kirby-paperback-export.git site/plugins/paperback-export
+    $ git submodule update --init --recursive
+    $ git commit -am "Add Kirby Paperback Export plugin"
+
+Updating the plugin as a Git submodule:
+
+    $ cd your/project/root
+    $ git submodule foreach git checkout master
+    $ git submodule foreach git pull
+    $ git commit -am "Update submodules"
+    $ git submodule update --init --recursive
+    
 ## Options
 
-By default, Kirby Paperback Export will include the text of every page on your Kirby site, including invisible pages. The following options allow you to select and filter which pages are included.
+By default, Kirby Paperback Export will include the text from the title and description fields for every page on your Kirby site, including invisible pages. The following options allow you to select and filter which pages are included.
 
 ```php
 // Include invisible pages