Reference 

The different tools in the ABAP Workbench provided for developing Web applications are explained in Web Dynpro Tools in the ABAP Workbench.

The various UI libraries and their respective UI elements are described in User Interface Elements.

As well as an overview of all the relevant URL Parameters you will find a list of classes and interfaces:

·        Controller Classes and Interfaces

·        Service Classes

For an introduction to developing with Web Dynpro you can use the Tutorials.

You can also see an overview of Using ABAP Dictionary Search Helps.