I think she means...like for example when you're driving, or sitting on the bus, or walking, or doing some repetitive task like washing the dishes..you naturally drop into that daydreaming "alpha" state anyway, and so from there you can just proceed with the visualizing.
I often do the technique when I'm travelling on the bus. I'm looking out of the window and the real world kind of receeds. So doing it then even with eyes open is fairly easy.