This is getting very confusing Dizzy. To make it simple, lets just concentrate on one file, and that is the project file, in the second link called intro_maketa.hype.
In that, I have 3 scenes, the first being the main one with the button:
In your exported folder, in the index.html you have the logo on the top centre, with the audio to the left of it:
But in the exported one from hype, you do not have the top bit. Why, that is what is confusing, as in both index.html and intro_maketa.html, the stack is embraced within the hype container div ?
Are you looking to have an iframe, that is completely outside of Hype, but on the index.html file. I cannot see where the logo and audio file is coming from.
But again, can we just work from the main project folder