Take a clear photo with a visible subject and background depth
Use a portrait mode or depth map if available
Separate the subject from the background in an editor
Create a duplicate layer of the photo
Mask the subject on the top layer
Fill the missing background areas on the lower layer
Add slight horizontal shifts to create parallax
Use a 3D photo app or editor if available
Export in a compatible 3D or motion format
View the result on a device or platform that supports 3D photos