Multi-layered dialog slide navigation

I have built a slide as a stack of dialog layers about half the size of the main screen. This will act as a help slide that the user can open at any time from a button in the corner of the main course. I want whatever main slide they are on to still be visible behind when the help dialog is opened. 

However, at this point my project is just one slide with a test button on it which displays the help dialog layers. For the real project, I would rather the button in the base layer navigates to a help slide which when closed returns the user to whatever slide they were on when they clicked Help. Since the help slide is a dialog, half the size of the main slide, I want to be able to see the main slide behind the help dialog when it appears, (The way it would if the entire help screen were just layers on top of the main slide.)

This help dialog has about a dozen layers in it as the user can click on items to bring up little paragraphs of text. I don't want to paste these dozen layers into every slide in my course. So when the user clicks the help button, can I navigate to the dialog slide while still seeing the main slide underneath, and then pop right back to the main slide when they exit out of the help dialog?

Or is it better to re-jigger my help dialog so that the text paragraphs are objects which appear and disappear rather than separate layers, so my help dialog is only one layer and I just paste it on every main slide?