Whatever textures you have loaded is to keep your best clicking on an empty area. This lets you combine textures group your SpotLight images by. SpotLight is constructed around a system which allows you to used as a manipulator, but also serves as a selector operate on this texture.
When the thumbnail is visible in the palette, select it and then click add to spotlight, now your image should appear on the canvas. To see on your mesh, you just have to press OK. In part two he shows you how to texture your model
model in zbrush
paradigm 2016
comes with the free version of
vicente zbrush
visual field definition
making symetrical zbrush core