Robinson Annulation - Aldol Condensation

In the second part of the Robinson annulation an intramolecular aldol condensation occurs.  Lets work our way through it.  First step an enolate is formed.  The enolate does a nucleophilic addition (attack) on one of the carbonyl carbons to form D.  Intermediate D is then protonated forming the Aldol product E.  Dehydration of E yields cyclic enone F.