Hi,
Not a lot of information here, but if the fans are operating you will need to do some troubleshooting.
The cooling system in a vehicle is a pressurised closed system.
If you have lost water from the system it is possible that you have a leak either from connecting hoses, water pump, radiator or head gasket leaking.
It may help to web search online for “how a vehicle’s cooling system works”
Or “points of failure in a vehicle’s cooling system”.
Other than that, it might be a good idea to visit a radiator repair shop for an assessment.
Hope this helps