Overlay slideshow on top of image

Hi, I am new to WordPress and this forum, so please be gentle with me, I am also not a programmer.

I have searched the internet and forums generally for an answer to my query but not found any solutions.

I am trying to place a slideshow on top of another image. Basically the image will be an iPhone and the slideshow will fit in the square screen as if an app is being used on the iPhone (hopefully that makes sense).

I am currently using the Esplanade theme, although this is not set is stone and I have tried with various themes, and failed.

I would be most grateful for any help.

Thank you in advance.