What is combined to make NADH?

Answer 1

NAD+ is reduced by the addition of 2 electrons and one proton (H+) to form NADH.

Or are you asking what makes up the structure of NADH? If that's the question, it consists of a molecule of adenine, 2 molecule of ribose, 2 phosphate groups and a reduced nicotinamide molecule. If you google "NADH structure" you'll be able to find diagrams of its structure.