Menu Items navigation WPF-MVVM

Hi.. I'm new to WPF MVVM pattern, I need a solution to navigate from one window to another window in WPF MVVM using MenuItem. For example I have a menu item like this on my MainWindow.Xaml.

file --> New
Open
Save
Exit.

When i select "New" i need to open a new window called "New.Xaml" .

please help me.I am new to wpf-mvvm.


Thanks,
Sri