When styling nHair, you often need to select a group of curves CVs to which you want to apply nConstraints. For example, to position hair curves, you may need to select the end CVs on each curve for a Transform constraint. Be aware that the components available to be selected depend on the current display of the hair system. Set the display to the curves' current position by selecting nHair > Display > Current Position.
See also Start Rest and Current Position curves and Set hair curve positions.