what happens during the first step of ozone formation in the atmosphere? pls give me quickly.

The word “ozone" is generally equate with the ozone layer, which is an layer in the stratsophere protecting the earth from the harmful ultraviolet (UV) radiation emitted from the sun.UV radiations are the cause of skin cancer.
The production of ozone occurs when oxygen O₂ rises to the upper atmosphere and is exposed to the sun’s UV rays.The UV rays then split the oxygen molecule,O₂ into two separate O₁ atoms.However the O₁ atom is very unstable it combines with an O₂ molecule to form ozone O₃.