Need some help with MVVM

Hi everyone i'm pretty new in WPF an Expression Blend4, at this moment i'm working on a project,i found a tutorial for building an address book, it is a address book which has a list box on it, it has a class with some contacts, an addressbookviewmodel class and a viewmodelentity class, in the main window i also have a button wich have the function to make new contacts. I want to add somethin more to the application i'm building,i want to add another 2 buttons ,one to save the new contacts i will add and another one to delete the selected contact, i also want to add and a textbox where i could search the listbox items. Please can anyone help me how to do it ...