Malware/virus? On Samsung note 3

Hello. I downloaded the avast to get rid of a possible malware on my phone. It’s a warning that says there’s 2 viruses and my battery is damaged and it will not go away!! It’s on my Internet. I scanned it but it comes back with no issues. How do I get rid of it! :-\

Honestly I would just do a clean boot and have a antivirus installed and keep it on. If possible download samsung smart switch and try to save photos and other important things onto an external and switch it back once you did the clean boot WITH the antivirus and scan the external drive as well.