Conservation of Genetic Material — DNA Replication

Nucleotides consist of an inside base such as A, T, G, or C, connected to a backbone of a sugar and a phosphate. The bases make up the 'rungs' of the ladder on the inside, while the sugar and phosphate create the length of the DNA. For DNA replication to occur, the new nucleotides have to be added in the correct order, connecting both the bases and the sugar-phosphates. Where are these new nucleotides placed as they are connected?