WPF Login as application frontend

I got my WPF login process working and now I want to take this application further so I can continue to learn.  Lets say I wanted to show another window instead of the "welcome" window.  So when login is clicked, instead of showing the welcome window, I wanted to show another window lets say to add customer information.  So instead of showing welcome, I show "customer information" and then do the code behind to handle all the editing of the data they input, writing the new records to the database and so on?  Is that how I'd do it and is that the way to do it?  Or actually I think the correct way is, login app is a stand alone object that can be used in any app.  Not sure how to create another app such as the customer app and the first thing to show is the login before customer app.