What are the key files needed to get a project up and running using Ext?  The following lists the bare requirements to get ext running.

  1. Download and extract Ext to a folder :[Ext Download].
  2. Create a folder to store your project in.
  3. From the [Ext Download] folder, copy ext-all-debug.js (or ext-all.js if you want the release version) to the project folder.
  4. Ext can run with *YUI (Yahoo UI), Prototype/scriptaculous, or JQuery.  Copy all the files found in the [Ext Download]\adapter\[your lib choice] folder to the project folder. 
  5. Finally copy to the project folder CSS and images folders found in the [Ext Download]\resources folder.

* My first misconception about Ext was that I needed to install the appropriate library (prototype / scriptaculous / YUI / JQuery) as well as Ext to get it to run.  The Ext distribution has all the files and source from those libraries that it needs to run. E.g. for prototype, it’s all wrapped up in the one file ext-prototype-adapter.js.

* Actually as efege commented Ext includes all the necessary files from YUI.  To run with prototype or jQuery you need to download and include these in your script block as specified by the respective library.  (I would expect that these need to be included before the ext and ext adapter script files)

You now have the basic libraries ready for use, add a html file and add the following script sections to the <head>.  Note the order, it is important.  In this case I have opted for the YUI adapter.  (replace the two YUI script includes with the appropriate file name for the other libraries)

        <script src="yui-utilities.js" type="text/javascript"></script>
        <script src="ext-yui-adapter.js" type="text/javascript"></script>
        <script src="ext-all-debug.js" type="text/javascript"></script>
        <link href="./css/ext-all.css" media="screen" rel="Stylesheet" type="text/css" />