The second half of this equation is “6H2O + 6CO2 + ATP”. However, photosynthesis to respiration would read “6CO2 + 6H2O + LIGHT ---> C6H12O6 + 6O2 ---> 6H2O + 6CO2 + ATP”. Every living thing does the cellular respiration part (from C6H12O6 forward). However, only plants do the first part with light, which we call photosynthesis. It’s actually pretty incredible; plants take our waste - CO2, or carbon dioxide - and light, add some water, and create their own sugar.
Cellular respiration creates ATP through something called the Krebs Cycle. This is a complex cycle, and takes a little more time to explain.
However, it does create between 30 and 34 molecules of ATP. This is because it makes the electrons work by going through an electron chain, and when the electron is done, it’s attached to the molecules that become water.