Following
@TrippyLighting 's screencast should get you there. I managed to get it to work, though the Project to Surface tool isn't terribly intuitive.
For the longest time I was getting an error about selecting the same Sketch to project to. Eventually I realized, once you've created the sketch you wish to select, you have to select Project to Surface and then 3 things. First, a plane in the direction of your projection. Then, the face you want to project to, and then, the Curve you wish to project.
Note how Trippy first selects the bottom plane, THEN selects the Face and the Curve he wants to project. I guess you need to define the projection direction or the plane orthogonal to your direction of Projection.
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"The future is already here - it's just not that evenly distributed."