link two windows in WPF + MVVM Light

Question

Good evening, I try to link the window WPF "MainWindow" with another window WPF that I name it "window". I write this code with MVVMLight Toolkit:

ViewModel / MainViewModel.cs

public class MainViewModel : ViewModelBase
   {
       public ICommand Save { get; set; }
public MainViewModel()
       {
ave = new RelayCommand(CommandSave);

       }
rivate void CommandSave()
       {
fenetre windows = new fenetre();
           windows.Show();

       }


   }

does this confirm the MVVM design pattern, or how can I fix it?