What does 'I hear and I forget I see and I remember I do and I understand' mean?

It means that actions are more important than Words, some one can say a million things and you will forget them if their actions dont prove/show their Words, and based on that you act a certain way and you understand it. What someone does you will remember, because those are actions, actions are real, Words are not always real/true they could be lies. This saying highlights the fact that many people learn a new skill or fact poorly if it is only heard. You learn and remember a little better when seeing the fact or a demonstration of how to do something, but the best learning of all comes from 'hands on' experience...actually getting and doing the thing you wish to learn. Many people learn this way, but others may learn best in a visual or aural way, as recent research into learning styles shows.