Your PAT is made up of four phases. Phase One and Two are the data modelling phases. Phase Three is the coding and Phase Four the testing.
Phase One – The project specifications. What your application does. A list of features.
Phase Two – The Design Document. How it does what it does. The primary storage, The secondary storage, The GUI’s and how they work together.
Phase Three – Technical Document. The code itself with comments, using OOP programming principals.
Phase Four – The Testing Document. How well does your application work? What does it do well? Where can improvements be made?
Here is an overview, with examples, for you to follow.