Installing Agile Toolkit for the first time
Download Agile Toolkit from agiletoolkit.org and unpack it into your webroot. If you area already using your webroot for something else, you can pick a sub-directory. The file you just downloaded, called atk4-example.zip, comprises 3 things: Agile Toolkit, Add-ons and a very simple example project structure.
Open index.php file in your browser and you should see "Hello World from your own copy of Agile Toolkit". You can see an example of what a successful installation looks like on our server: http://example.agiletoolkit.org/ If you see the same in your own server, then you are ready to proceed to the next step.
Upgrading Agile Toolkit
Go to "download" page and pick "atk4-x.x.zip" and "atk4-addons.x.x.zip". Expand those archives and move the "atk4" and "atk4-addons" directories, replacing the ones already present in your installation.
If you are using Linux, then you probably already have Apache installed. You can also use more complex configurations such as Nginx + PHP-FMP or lighttpd for improved performance.
If you are familiar with Git, you can also "clone" atk4-example instead of downloading it. Alternatively, you can create your own repository and attach atk4 and atk4-addons as submodules to it.
$ git clone git://github.com/atk4/atk4-example
$ cd atk4-example
$ git submodule init
$ git submodule update
Finally, if you are looking to share your web application with others, we suggest you use Platform as a Service, offering PHP hosting in the cloud. It will take care of your project deployment for you, and will let you focus on development. Agile Toolkit is well tested, and should work with most PHP platforms. Two deployment platforms which we recommend are: