How to create a surface like attachment ?

Hello, I want to create a surface like the yellow one in attachment, but i found it’s hard to curve form a plane.

Is there a correct way to do that? Please share your suggestion.

Attachments


I start from cylinder and add Subsurf modifier to round it up:

Attachments


Sorry, can not understand completely.
Does the “cylinder” is a default object, such as “Cube” and “Monkey”.
I can not find “cylinder” in my v2.5 blender, how to add the obj ?

It’s called ‘Tube’ in blender 2.5