Answer:
ATP works as "currency" for intracellular energy transfer. NADH's cell's tool for accepting/donating electrons.
Step-by-step explanation:
To be fully functional, all cells need energy, ATP is the molecule that provides cells with it, for this to happen one of the phosphates groups that forms ATP needs to be broken off from it to release energy.
NADH is a coenzyme formed after NAD+ is reduced, this makes it a reduction agent that can donate electrons, this can help to glucose oxidation during glycolysis.
The production of ATP and NADH during Aerobic Cellular Respiration happens in different stages, during glycolysis 2 ATP and 2 NADH are produced, in a link reaction another 2 NADH are produced and finally, during Kreb's cycle 2 ATP and 6 NADH are produced.
I hope this information helps you understand a bit more about how Aerobic Cellular Respiration works!