SW Drawings inserted into Parts for Contour Selection

I know I have seen this in years past with presentations where you can

take a Solidworks 2D drawing and insert it into a part file and use the

contour select tool to extrude and create features from.

I thought I remember in the presentation this being done then in feature being able to select the lines

from the drawing to inibit the countour select tool.

How is this done?

Thank you

SolidworksParts And Features