1. Change your experiences
The understanding is that you are what you do; and the idea is that to improve your life by doing different things - doing more things that make you feel better and avoiding things that make you feel worse.
2. Change your consciousness
The understanding is that you are how you think; and the idea is that if you can improve the way you think, then even doing the same things will make you feel better.
3. Change your understanding of life
The understanding is that life needs purpose to have meaning; what needs to be changed are the basic assumptions concerning the purpose and meaning of human life and the world. - how everything fits-together and your personal role. The aim is to reframe reality.