As the title says:
What is the basic graphic pipeline flow used in Esenthel engine?

EE uses Deferred, Forward, or Simple (Fixed Function) rendering.

You decide which method to use, but I believe EE automatically changes depending on the hardware. Someone correct me if I'm wrong on that point.

Deferred looks the best, uses every feature and works on any SM3+ card.

Forward will work on SM2+ cards, but doesn't support as meny features. For example, the number of dynamic lights is restricted when using Forward rendering.

Simple rendering used the Fixed Function pipeline and should work on pretty much any video card. Of course it doesn't look the best, but it is still quite good.

I think that Deferred rendering works on SM2 too, but some effects are unavailable like Volumetric Lightning.

Graphic pipeline flow, sounds like he means how to handle importing meshes etc with the least advanced and easiest way of doing it