Freuds theory of Psychodynamics is based on three levels of consciousness. The conscious, preconscious and unconscious.   The conscious level is all the thoughts we are aware of, ie something you are reading or watching, something you are remembering, or your emotions. The preconscious level is not immediately available to us, but can be brought into the conscious level. A good example of preconscious thoughts are memories. The unconscious level contains a great deal of thoughts are 'repressed'. For example traumatic memories, thoughts that are emotionally harmful.
The three structures of personality are the ego, superego and id. These three parts of the personality all clash and interact, and our actions are typically based on a combination of all three.
The id is the primal desires of the personality. Ie, sex, food, sleep, thirst. The id is based on the pleasure principle, and demands instant gratification without even considering the consequences.
The ego is the logical and 'thinking' part of the personality. It keeps the id in check, as it reasons that gratification is not always instant and considers the consequences.
The super ego is the center of morality in the personality, and decides whether or not the actions induced by the ego and id are moral. The superego causes us to feel guilt over doing something wrong, and pride over doing something right.

Freud wrote that during a childs psychosexual development, they would progress through seperate and distinct stages, all based on an area of the body that provide the focus of pleasure (The erogenous zones). These stages are the oral, anal, phallic, latency and genital stage. Freud also theorised that an individual can become fixated on one of the stages, leading to neurosis related to the stage in question.
The oral stage occurs from birth to approximately 1 to 2 years of age. During this stage the Id is dominant, and the child operates solely on the pleasure principle, however the ego is in formation...