Create a short GIF file based on a backgroung and a front photo

Hi,
I want to create a short Gif (4 to 6 sec) based on two photos I already have : a background photo and a photo of a hand holding a mobile phone. I will provide a few photos (to select together the best to be used together with the freelancer) after validation of the project.
Please find here bellow and example of similar sequence as the one I wish to create :
https://www.shutterstock.com/video/clip-1091691155-4k-mobile-phone-chroma-key-app-application
Thanks