Import contour line as CAD, and generate surface.

You can import surface from graphics and when you do, you must assign a feature name, a feature style and a feature type. The name can be anything. I recommend "contour" without the quotes. InRoads will add a sequence number as you import multiple contour elements. The style is important for later edit or review. It must make sense in the feature style settings for a surface feature. Finally, the contours must have elevation. If imported as contours, they must be planar. It is also recommended that there be no gaps.

InRoads has a generate inferred breakline tool that helps eliminate flat areas, but gaps in the contours confuse it.