So I built an example, since it wasn’t going to take very long to do.
A couple of things. Un-tick the fade option on the modals or it will flicker when it changes. I have also added a couple of screen shots of the settings for the Next button.
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Panel settings for the next button on the modal. This is probably where it was confusing. because you can use the interactions type to set the href. Set the type to “Toggle Modal” and then the modal ID of the next modal you want the button to go to.

You only need to add the one extra custom attribute, because the Modal bric already adds the data-toggle one.
