How do I troubleshoot an overheating engine in my Audi 80?

My car's engine temperature gauge is reaching the red zone and I'm worried it might overheat. What should I do to troubleshoot this issue?

Check the coolant level and make sure it is at the recommended level. If it is low, refill it with a 50/50 mixture of coolant and water.

Inspect the radiator for any blockages or leaks. If there are any, have them repaired immediately.

Make sure the radiator fan is working properly. If it is not, it may need to be replaced.