While most of the theories begin with the origin of life or existence in physical dimension, the Vedanta deals with the concept of origin of consciousness.
For something or being to be conscious of its existence or its surrounding, it has to have limitation or existence of others/ surroundings to become aware of. An existence without the other can not experience awareness or consciousness.
Thus Vedanta says that in order to experience Itself Brahma or the Ultimate Existence initiated the creation of Universe or Brahmand. The process of creation was initiated with the beginning of consciousness which could help It to experience and perceive the other.