Photo slideshow
How do I set up a slideshow on my iPad?
The iPad User Guide is a rich and frequently overlooked source of information about iPad and iPadOS. Here is a direct link to the appropriate chapter of the Guide:
Play videos and slideshows in the Photos app on iPad - Apple Support
For reference, the full User Guide is available both online (using a web browser - such as Safari), or as an Apple Books download:
iPad User Guide - Apple Support
https://books.apple.com/book/id1567104892
The Tips App, installed by default on all new models of iPad, provides a brief introduction to iPad - and leads you to the User Guide. In case you missed it, here is a link to the Tips App:
https://apps.apple.com/gb/app/tips/id1069509450
Apple also has a huge YouTube Channel - containing videos and feature guidance: