The document you are reading attempts to explain some basic concepts of EFL rather that act as a programming guide. If you are looking for technical information regarding EFL, take a look at the guides written by the developers themselves. Available guides are:
The EFL Cookbook
The EWL Book Reference
The Edje Book
The EFL Cookbook contains common recipes for most EFL components. A good read in order to discover some of the endless possibilities of EFL.
The EWL Book provides background on the common widgets provided by EFL. If you need to use EFL as a GUI toolkit, this is the proper document.
The Edje book contains almost everything you need to develop themeable EFL application which use the Edje Layout engine. Make sure that you know a bit about Evas (the EFL canvas) before reading this document.
If, on the other hand, you need to dive straight into coding, consult the reference documents for core EFL libraries. These are generated automatically by Doxygen, so they are the closest thing to code documentation apart from code itself. Available reference guides are:
The Ecore Reference
The Edje Reference
The Eet Reference
The Evas Reference
The EWL Reference
All of the documents mentioned above can be downloaded from the Documentation page at the Enlightenment website.
You can always look directly into the source code. Most of it is well commented. The syntax is clear and straightforward. If you become familiar with functionality not already documented, consider sending a patch with needed documentation.