What is malaria and how can children be protected from it?

I would like to understand what malaria is, how it spreads, and what practical steps parents and caregivers can take to protect young children from infection. What are the early warning signs of malaria in children and when should a child be taken to a health facility? Are there vaccines, medications, or preventive measures that are recommended for children in malaria-endemic regions? I am looking for clear, practical guidance that a parent or community health worker can act on.