If that can help :)

As a form like this can't be SuDivided directly (Top face more than 5 edges)

Use SSPlit for trim
Use SBridge for "Blend Faces" only 2 by 2
Use _SUbD for SubDivide



Copy / Move faces
Bridge them



Extrude to Point or Nsided (kill the caps before) can be used for simple form :)