// in app/Providers/NovaServiceProvider.php

// ...

public function cards()
{
    return [
        // ...
        new \Tightenco\NovaGoogleAnalytics\PageViewsMetric,
        new \Tightenco\NovaGoogleAnalytics\VisitorsMetric,
        new \Tightenco\NovaGoogleAnalytics\MostVisitedPagesCard,
        new \Tightenco\NovaGoogleAnalytics\ReferrersList,
        new \Tightenco\NovaGoogleAnalytics\OneDayActiveUsersMetric,
        new \Tightenco\NovaGoogleAnalytics\SevenDayActiveUsersMetric,
        new \Tightenco\NovaGoogleAnalytics\FourteenDayActiveUsersMetric,
        new \Tightenco\NovaGoogleAnalytics\TwentyEightDayActiveUsersMetric,
        new \Tightenco\NovaGoogleAnalytics\SessionsMetric,
        new \Tightenco\NovaGoogleAnalytics\SessionDurationMetric,
        new \Tightenco\NovaGoogleAnalytics\SessionsByDeviceMetric,
        new \Tightenco\NovaGoogleAnalytics\SessionsByCountryMetric,
    ];
}