What combines with sugar and a phosphate group to form a nucleotide?

In terms of bonding, there is the presence of ester bonds. This happens when the OH group of the nucleotide is reacted with an inorganic phosphate group from phosphoric acid. there is also the formation of anise groups through the reaction of amines. overall formation of a nucleotide is mainly due to condensation reactions through hydrolysis(water out) from H and OH from the different molecules. Also there is the formation of phosphoester bond between the whole molecule

Very hard to understand