Give the steps in the contact process and what happens in each step

Sulfur is burned in air to get oxidised to form sulfur dioxide Sulfur dioxide is mixed with more air with the catalyst vanadium(V) oxide at 450 C for sulfur dioxide to get oxidised and form sulfur trioxide It is then dissolved in concentrated sulfuric acid to form oleum It is first mixed with sulfuric acid instead of directly adding to water as if it is added a dangerous mist of acid will form Oleum is then mixed with water to give concentrated sulfuric acid