Hello, what is the best way to protect my computer?

I'm slightly tech illiterate but I want to at least be aware about these things and start taking better care of my things. I just downloaded Avast when I reinstalled my operating system awhile ago and I basically called it good to go, but I've been wary about it.

I tried streaming a movie tonight (something I don't really ever do), which made some flags go off with Avast, but I scanned, and it doesn't look like anything terrible happened. Regardless, it made me realize how poorly protected all my shit is.

I was recommended Norton + CCleaner by a friend, but I don't know if there are other, better options. I have also heard that you are supposed to have an antivirus & antimalware both. Please help.

Also, the thing that avast caught was called, "JS:Miner-C [Trj]".