As you can probably see, the camera is moved forwards(, usually on a dolly,) and the lens on the camera is zooming out at the same time to create an effect called a dolly zoom. This camera technique was made popular by martin scorsese in the hit movie, "Vertigo". This should hopefully teach you how the famous camera technique, the "Dolly zoom". The Dolly zoom can also be known as The vertigo effect. A good 3D representation of a dolly zoom here: https://scratch.mit.edu/projects/119024984/
made entirely by me and the power of scratch's game engine give you this international animation of how a Dolly zoom works.