Then tell us what you want to do with the photo. If you have followed some of the basic tutorials in the User Guide you will know how to animate position, rotation and scale of the layers.
If you want to separate foreground and background elements in a photo and then create moves that make the photos look 3D you need to separate the elements in Photoshop and then do the animation in AE using 3D layers.
If you want to isolate parts of the photo and add effects like glows or animated lines then you need multiple layers and some way to mask the photos. The most efficien workflow depends entirely on the photo and what you want to do with it.
The still you posted does not tell us anything about your sample except that it looks like a screenshot from a phone.