1. What does the Overprint icon do?
The Overprint icon at the top of the panel displays a simulation of how blending and overprinting appear in color-separated output. Toggling the Overprint icon also re-loads the file. The default is toggled on.
2. What does Layers do?
Layers lets you display layers/ separations. All layers are selected by default.
3. How do I select layers and/or separations to include in the inspection?
Click Layers on the side panel via the Toggle Side Panel button). Check the layers and/ or separations you want to display. The Spot Layers (separations), CMYK Layers, and Layers icons at the top of the Preview panel toggle between which are viewed under Layers on the side panel at a given point in time.