Loop on the first slide of a presentation.

Hello,
I would like to have a first slide with several animations on text blocks or images that play automatically (fixed order, calculated duration...), and while the audience is getting seated, this slide should loop indefinitely, with a click allowing the actual presentation to start at slide 2.

I haven't found a way to do this except for something that I only partly like: to make this specific slide a looping presentation with a button that, when clicked, would launch a second slideshow of the other slides.

Thank you for your suggestions

Noël

PS it’s on Office 2007
Configuration: Macintosh / Chrome 76.0.3809.132