After the primer is in place on a single, unwound polynucleotide strand, DNA polymerase wraps itself around that strand, and it attaches new nucleotides to the exposed nitrogenous bases.

the helix structure is unwound special molecules break the weak hydrogen bonds between bases, which are holding the two strands together this process occurs at several locations on a DNA molecule ...

including the unwinding of DNA and the copying of the two unwound DNA strands. The process is akin to a factory assembly line where balls made up of massive, crumpled strings of data are unraveled ...