Welcome. This is just a <header> with position: fixed
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Freeware Photo Slideshow by WOWSlider.com v3.4

This is the Wow! slider free version (non-commercial, or commercial up to two machines).

This one has a .exe file that runs a wizard—no code needs to be understood (both good and bad thing). I added some CSS to my page to center it and make it smaller. Note that the wizard makes folders called e.g. engine1 and data1. I used the option to publish into an existing HTML page. Also when I add text, the images resize, so try to set up your page first.

Q: How is the slider script called (started)? And how did I make the header (HTML5, position:, z-index, negative margin, etc.) and why did it disappear with Wow!?