It's a description of the learning process. For example, someone might tell you how to drive a car. If all that happens is that you hear the instructions, you'll never remember them. If, though, the teacher takes you to a car and you sit there watching how he drives, you'll remember lots of it. The best way, however, is to sit in the driver's seat and actually drive the vehicle. Then you'll understand what to do.
A friend of mine is doing a refresher PGCE to return to teaching after bringing up a family and this is one of the things the trainee teachers are tought.