The API Reference describes each object, method, and property in PowerPointWriter.
PowerPointTemplate is the main class for template-driven document generation. This object opens a PowerPointWriter template file, populates it with data from a specified data source, and generates a new PowerPoint presentation.
PowerPointApplication is the main class for pure code-based workbook generation. This class is an engine used to open, create, and write (save or stream to a browser) presentations. A single instance of PowerPointApplication can generate multiple PowerPoint presentations.