Looking for short cut?
Shortest possible route to theory
Now as you do not wanna go through all the content as it is too much to read, here is shortcut to give you a quick idea of DFD. Just read these:
This should help you cover the basic idea.
Shortest possible route to implementation
If you could get the basic idea and you still have enough energy and curiosity to know how to implement DFD, try reading about the approach.