Woke up to this screen (American Megatrends) and not sure what it means or what to do

I’ll start off with the fact that I don’t know much about computers. My ex friend built my PC, and I would like to learn one day. I woke up to this on my screen, and hitting F1 brings the second image. I dont know what to do on second screen. I can see it obviously says CPU fan error, but also don’t know what to do with that info. Any help?