The extended form behavior code doesn't go within the form embed code, it goes after the standard form embed code.
So there's no need to specify the Munchkin ID nor the Form ID, since it works with whatever form(s) you have embedded on the page.
If you're not comfortable with the structure of an HTML doc (i.e. where to place <script> elements vs other HTML elements) you'd probably benefit from engaging a developer for this very small project. It doesn't require a coder per se but you need to know how pages are laid out in general.
Ok I see what you mean. So this code would be a layer on top of the form on the Marketo landing page, right?
I sent the request to our web developers, as the form need to live out our company website. I assume they shouldn't have an issue with figuring out layers there.
I'm hesitant to use terms like "layer" or "on top of" since scripts aren't part of the visible layout. But I'm sure they'll know what to do.