Ex : when you grab and move around a position tracker instead of an object and you see the object on the screen, not in your hand.
When you hear a sound instead of touching or when a colour tell you that it is hot or dangerous.
When you show where you want to go (The superman Metaphor)
When you say to the user, to get that, you should do that, because it is as if you were in such another situation (The "world in your hand metaphor")
Driving a car could either be a schema, a schema by substitution (you say : "drive me to the biggest house") or a metaphor ("use the keyboard to steer and change the speed and you will move as if driving a car")
The best is of course the Schema (Natural immersion), but it is not always possible or of good quality, and often the other solutions are then better (more efficient)
From the desktop to the web crawling ("click on the blue text to get" or ... to "get the page") and to the move around ...