I want to create a slide show of about 25 images for my landing page

Hi everyone. 

To date I've asked for help twice already and all the info I've received has been REALLY helpful. So thanks to all who contributed. It is GREATLY appreciated. 

Now, my new thing: I want to create a slide show of about 25 images which I want to start showing as soon as the visitor hits the page, and use it as a promotion for the landing page, which is the page with the Statement and Bio information. Basically I want to offer one of those images (or ones like them) as a free gift to new buyers from the website. I want to be able to change the images I use every month or so. 

My question is: how do I go about creating this? Normally I'd use PowerPoint to create a slideshow, but I don't think that would work here. I know I can upload PowerPoint to YouTube and I was planning on doing that anyway, but I don't think I can have the YouTube video on the SquareSpace page (not so familiar with how YouTube works anyway, truth be told). 

I've seen something like this on pages made with other platforms, so I would imagine it's a doddle to do once you know how. 

Thanks in advance, lovely people. 

Orla 

If Slideshow with images only, you can add a Gallery Slideshow Section

https://support.squarespace.com/hc/en-us/articles/360035636332-Gallery-sections