There are Nitrogenous bases ( Adenine = Thymine) [ linked by 2 hydrogen bonds ]
(Guanine = Cytosine) [ linked by 3 hydrogen bonds ]
That nitrogenous bases are connected to de-oxyribose sugar through glycosidic linkage and forms nucleoside
Finally, that nucleoside bonds with phosphate group through phosphodiester linkage to form nucleotide, which is main component of DNA
Hope this helps!