Step-by-step explanation:
Freud wanted to analyse the dreams of the people because he thought that this is the only and easiest way to understand the unconscious activities of one's mind. He believed that the thoughts or wishes which were suppressed by the individual comes as a disguised fulfillment in his dreams. The person sees in a dream which he always wished for.
Repressed thoughts or repression explains the thoughts or desires which are shameful or distressing. So you hold such emotions inside your self and don't discuss about it with anyone.
Unconscious mind is the part of mind which is a pool of thoughts, feelings, emotions and memories which are not present in our conscious mind. These are the thoughts which are activated at the back of the mind.