How to activate microphone on new laptop

What problem are you having?

The Microphone is already activated when used by the OS and apps must first request permission to access the Microphone. If that permission was initially denied, then you can go to  > System Settings > Privacy & Security > Microphone, and turn it on. You won't see an app there that has not first asked for your permission and it is the apps responsibility to request the permission at an appropriate time.

The microphone is activated by an app that has access to the microphone to use it. You don't just "activate it" and turn it on when you wish.

See Control access to the microphone on Mac

Control access to the microphone on Mac - Apple Support