How did Creation come into existence?

With the exception of mankind, we are only told what God made, not how He made it. That fact is in order to stress mankind's importance.

To make man, God fashioned the appropriate shape from dirt and breathed a soul into it (Genesis ch.2). He then made the first woman by fashioning her from a piece of the man's flesh (ibid).

Day by day, God created the universe and its contents (Genesis ch.1).God created the universe out of nothing (Exodus 20:11, Isaiah 40:28; Rashi commentary to Genesis 1:14; Maimonides' "Guide," 2:30).Note that the Torah, in describing the Creation, deliberately employs brevity and ellipsis, just as it does in many other topics. See the Talmud, Hagigah 11b. And: How many Creation-narratives are there in Genesis?

• On day 1: God created the universe in general, light, and this Earth. The light was not the same as that of the sun. Rather, it was light that God created before the sun, and which emanated from a point in space without any physical source; like what we might term a "white hole."
  
• On day 2: God created the separation between the Earth and the upper atmosphere.
  
• On day 3: God separated the continents from the oceans, and created plants.
  
• On day 4: God created the sun, moon, and stars.
  
• On day 5: God created birds and fish.
  
• On day 6: God created animals and people.
  
• On day 7: God ceased creating, thereby creating the concept of rest.
  

See also:

Is there evidence for Creation?

Can you show that God exists?

Seeing God's wisdom