How to use the ngx-tour-ng-bootstrap.TourNgBootstrapModule.forRoot function in ngx-tour-ng-bootstrap

beforeEach(async(() => {
    TestBed.configureTestingModule({
      imports: [ RouterTestingModule.withRoutes([]), TourNgBootstrapModule.forRoot() ],
      declarations: [ ProductTourComponent ],
      providers: [ TourService ]
    })
    .compileComponents();
  }));

@NgModule({
  declarations: [NgBootstrapComponent, DocsComponent, OtherRouteComponent],
  imports: [
    CommonModule,
    RouterModule.forChild([{
      component: NgBootstrapComponent,
      path: '',
      children: [{
        component: DocsComponent,
        path: '',
      }, {
        component: OtherRouteComponent,
        path: 'other',
      }]
    }]),
    TourNgBootstrapModule.forRoot(),
  ],
})
export class NgBootstrapModule { }