I'm not sure I'm understanding Your question but if You refer to populating Items I do it like in sample by Ioc in constructor of my conductor
public MainPageViewModel(INavigationService navigationService, HomeViewModel homeViewModel, LibraryViewModel libViewModel, StoreViewModel storeViewModel, SettingsViewModel settingsViewModel)
{
this.navigationService = navigationService;
this.Items.Add(homeViewModel);
this.Items.Add(libViewModel);
this.Items.Add(storeViewModel);
this.Items.Add(settingsViewModel);
}