You need to install the UTM virtual machine manager In your browser, go to mac.getutm.app, and click on the Download button.
Mount the downloaded UTM.dmg disk-image and drag the UTM app to the Applications folder. Next, launch the UTM app from your Mac’s local Applications folder. (Depending on your Mac’s security settings, you may get a confirmation dialog when you launch UTM for the first time. If such a dialog appears, choose Open.)