How to plot a PDF that shows multiple Layouts and Layer States for a project?

[#1]

Hello! I am very new to AutoCAD so apologies if this question is pretty basic.

I have a Parcel map with an outlined Buildable Area based off of the surface topology and hydrology. I am hoping to create a PDF that shows the Buildable Area map with the Hydrology data overlayed at multiple levels of detail. 

I created 3 Layouts, and saved a Layer State for each that specified which layers to leave visible:

• All Hydrology data maps
• 1'+ depth map
• 2'+ depth map

So my question is what is the process for creating a PDF that shows each of those Layouts/Layer States on one page with a shared Legend? Additionally, the hydrology data extends well beyond the true area of interest. I created a layer with a "bounding box" that I would like to use as the Extent for the plotted image. 

Thank you in advance!

[AllenJessup]

You'll have to create one Layout with three Viewports plus your Titleblock and Legend. Control the layers by using Layfrz to VPfreeze the unneeded layers in each Viewport. You can also freeze the layers in the Layer Manager.

[MMcCall402]

Copy the three viewports to one layout tab.  Move the legend to paperspace, or in its own viewport.  Print that tab to a PDF.

[#4]

I decided to start by just making a page for each of the three views, and adding them all onto one layout is now a process I think I understand. Currently my issue is with the legend, specifically that when I create a legend from the viewport it is empty. 

My goal is now to create a legend that summarizes the different layers shown in the viewport. When I got to Layout Tools --> Layout Elements --> Legend and select the viewport, the legend that is generated is still empty. See pic for refence, "Legend" is below the City Name prompt.