to get you on your way - watch the videos that Harry page has done -
see them here
now basically going through you need to select your view to change with the histogram, then select the real time preview, then after that you look for the triangles below, grab the middle one, now you can move that up or down - as shown.
after you have had your play around you then select the new instance button, grab that and then drag it over the top of the image you then want to change and drop (after you close down the real time preview)