How do the chromosomes arrange themselves after fertilization in humans?
After fertilization the diploid cells divide by mitosis.  Chromosomes don’t need to pair with their partner during the eukaryotic cell cycle.  After S-phase each chromosome has been duplicated (so there are 46 + 46 = 92).  The two daughter chromosomes resulting from semi-conservative DNA replication are held together at one point: their centromeres. In M-phase two microtubules from opposite poles of the mitotic spindle will attach to the kinetochore that assembles at those centromeres.

Nowhere in this process is the maternal chr1 required to interact with the paternal chr1.

The pairing that you are refering to takes place much later after the new primordial germ cells haved developed into the germline, leading to meiosis.  The molecular details of homolog pairing during meiosis are best understood in the model organism C. elegans where each chromosome has specific cis-acting sequences that are recognized by different trans-acting factors that lead to recognition and then pairing, followed by synapsis, and eventually crossing over.