My first contact with entropy was in chemistry and thermodynamics and I didn't get it. Actually I didn't get anything from engineering thermodynamics books such as Çengel and so.

You must go to statistical mechanics or information theory to understand entropy. Or trying these PRICELESS NOTES from Prof. Suo: https://docs.google.com/document/d/1UMwpoDRZLlawWlL2Dz6YEomy...