Virus on MacBook Air 14 ?

i honestly don’t know what’s going on, but I tried downloading a YouTube video into my MacBook and then all of a sudden my computer started going crazy and started saying I had a virus that it was detecting a virus and now on my Safari it keeps sending me notification stating ““ mac at risk! secure now from macosx-update.com protect with our antivirus today“ and I’m not sure if it’s real and also I’m not sure how to access settings on safari. I’ve been trying to see if I could delete.