Jobeda Ali

Hello, I am a new driver and just bought an old 2003 petrol C3 as my first car. I have no idea about anything to do with cars. For two months everything has been fine, but a few days ago the engine fan started running really loudly in the car. The first day it was quieter, I had never heard it before but i figured it was ok as sometimes engines get hot and need a fan. But the second day it was really really loud and I was so concerned I almost stopped driving. I haven't had the courage to drive it since. I thought maybe it needs water to cool down, but the manual says nothing about where the water goes. It was fully serviced and MOTed when I bought it two months ago so I can't imagine the coolant is gone. Any advice or suggestions please? Sorry for such a naive question. Thanks.