Can anyone help me with a link to a cool tutorial on how to make AI thumbnails, especially the realistic face generation options?

I want to add a carousel in yt shorts. Does anyone know the dimensions in which places to not place texts so that they are not visible behind the system yt icons? I mean the ones on the right and at the bottom. What margins should I make?

https://www.loom.com/share/baa340b812a1487e8ba175387601a19c?sid=047829d0-59e1-4b85-8d93-dd2e46618450