New IMac - old norton and malware transferred and need to remove

I just opened up my new IMac and transferred the data over from my old Macbook. (The Macbook has the Norton and Malware that I used because my system was 10 years old.)

I want to remove everything Malware and Norton from my new system.

I do not have a renewed subscription and I have not signed into the software.

What is the smartest way to do this?

Thank you.