On the BlueSurf command bar, click the Insert Sketch Step. You must select a plane to insert a sketch on. All of the plane creation methods are available.

In the following example, the parallel plane option was selected. Reference plane (1) was selected as the plane to be parallel to. Reference plane (2) can be dynamically dragged to the location to insert a sketch. You can also key in a distance. Click location to insert a sketch (3).

Insert a sketch (3) in the guide curve direction and notice the results. The parallel plane is used again.

Now turn off the reference planes and observe the results.

When the guide curve direction sketch was inserted, it crossed another sketch. The BlueSurf command automatically inserts BlueDots at the intersection of the curves. If there were several sketches in the cross-section direction, the inserted sketch in the guide curve direction would be connected with BlueDots.