Help need on Diff tool or Diff window architecture usage.

Hi,

I am writing a VCS plugin in which I want to use the Diff window of
IntelliJ.
I have implemented DiffProvider interface, and extended VcsRevisionNumber
class. I have also overridden getDiffProvider method in a class which
extends AbstractVcs.
But I am not exactly sure how this whole architecture works and also if l I
add a compare action, how will it by default call the DiffProvider.

Any pointers in this respect would be of great help.

~Priya