How do I delete virus files??

I have a MacBook Air and my computer has been very iffy ever since I bought it (using a dodgy charger will make the whole thing restart) and about 6 months ago I looked at a baby naming website that spammed me with notifications from “settings” that said I had a virus and had to download some random file. Didn’t download the file and just turned off notifications from that website.

Now to today; my computer, randomly just started showing me a malware alert (one that looks like a real alert, not anything like the fake alerts I got before) telling me I had downloaded a file called “ClassroomModeforMincraft2”- then when I click “move to trash” another alert pops up saying I downloaded “LearningNumbers-GamesforKids2”- I click the same and the prior alert shows up, etc etc.

I use my computer for writing and emailing- I haven’t even used Minecraft on this computer, let alone classroom mode. Let me know how I can get this off my computer, or at the very least how I can turn off the alerts- it’s super annoying.