Blend Tool - Blend along a curve
Dimmed unless you have either (a) a blend and a line, bitmap or shape selected or (b) a blend along a curve selected.
If you have a blend and a line, bitmap or shape selected: fit the blend to the line or outline of the shape. Note that this converts QuickShapes to simple shapes (that is, you cannot later use the QuickShape Tool to edit them). Also select Rotate along Curve if you want the blend objects to orient with the curvature of the line or shape. See Blending along a curve.
If you have a blend along a curve selected: separate the blend from the line or shape.