What did Freud mean when talking about the 'Unconscious Mind'?

Freud was a psychodynamic psychologist who developed the theory of the unconscious mind. As humans, it is believed that we only have access to a maximum of 10% of our brains and the other 90% is inaccessible. Freud described the brains structure to resemble an iceberg, the 10% is what we see above the surface. However, underneath the surface is the other 90%, the unconscious. Freud's theory states that throughout life we experience things that are far too painful and traumatic to process, therefore we lock them away in our unconscious mind as a coping mechanism. Although within everyday life, we do not have access to our conscious mind, Freud believed there are some ways of accessing it. Freud believed that when we sleep we are able to access our unconscious mind as all our defence mechanisms are down. it is believed that our unconscious mind governs our behaviour.