Pitched surface

I AM NEW TO RHINOCEROS, I Use the [CreateUVCrv]command on the cylinder side to create curves that represent the border of the surface on the construction plane.A rectangle is created.
I Use the [PlanarSrf] command to make the rectangle into a surface and then proceed pitching it but failed to execute the **[FlowAlongSrf] command. Is it a way to something about it?

Hello - can you describe what it is you are trying to accomplish? FlowAlongSrf takes a base surface, a target surface and some objects to flow… is that what you have?