In order to create an identical DNA we should study semi-conservative model of Stahl & Mosselson. There are three main steps:
1) An initiator protein unwinds a short stretch of the DNA double helix.
2) A protein known as helicase attaches to and breaks apart the hydrogen bonds between the bases on the DNA strands, thereby pulling apart the two strands.
3) Then, it replicates into similar half, so they get double in number, like 4 from 2, 8 from 4 etc. Hence, you have created a DNA molecule
Hope this helps!