Hi,
I would recommend to watch Steinberg Cubase Quick Start Video Tutorials.
Be aware, some menu entries has been renamed since Cubase 10:
- Devices = Studio
- Device Setup = Studio Setup
- VST Connections = Audio Connections
Btw, on Mac, make sure Cubase has enabled Mic in the System Preferences, please.
Open macOS System Preferences > Security & Privacy > Privacy > Microphone. Enable Cubase here.