ZBrushCentral

hair doesn't work?

I’m just messing around for the most bit, but I just downloaded some free hair brushes
I’ve added the brush and sculpted it onto the female head, but I don’t know how to add more hair with that brush

after adding the stroke of hair I wanted, I tried just clicking separately from the first, but it just replaces the first stroke?
I tried cntrl + click outside of the mesh, but the stroke still replaces the previous?