Use the Line tool or the Pick Line tool to draw a reference plane.
 (Reference Plane).
 (Reference Plane).  Work Plane panel
Work Plane panel
 (Reference Plane)
 (Reference Plane)  Work Plane panel
Work Plane panel
 (Reference Plane)
 (Reference Plane)  Work Plane panel
Work Plane panel
 (Reference Plane)
 (Reference Plane)  Datum panel
Datum panel
 (Reference Plane)
 (Reference Plane)  Draw panel
Draw panel
 (Reference Plane)
 (Reference Plane)  (Line).
 (Line).  (Pick Lines).
 (Pick Lines).