Redirect non-admin after login, and in url – /admin

All functions place in functions.php of your theme. And create redirect on template_redirect hook.

add_action('template_redirect', 'make_redirect');
function make_redirect() {
    if ( ! is_admin() && ! current_user_can( 'administrator' ) ) {
        wp_redirect( 'https://google.com' );
    }
}