How lupus damages organs like kidneys, heart, brain or skin?

Works on self: your body and immune system is working against each other that is why the multi system involvement as you mentioned

Autoimmune, systemic: Lupus is an autoimmune disease, in simple terms, your body produces certain antibodies that attack your own organs.It can affect any part of the body. Common symptoms - joint pains, facial rash, photosensitivity, mouth ulcers, hair loss. Organ involvement usually kidney, brain, and heart can occur. It is believed that genetic, environmental factors play a major role.