C# :: Multiple Pages On WPF Button Click

For now the app creates a new DateTime property which is binded to a label and shows the user the current time. Eventually I want to have the ability to select the timezone you are in, change font/background colors/etc etc... But that is all in time. My current step that I am trying to implement is having a button click (Binded to an event method) change screens. I find it hard to explain in words, but I would like the same Window to be used, just have different functions on the other when the button is clicked. So for example...

The only way I have found to do this so far is to create a whole new form or create tabs. While those are all good and have their place. I know that I need to start breaking up my code into classes, I am developing a bad habit throwing everything into the MainWindow Class...

Here is the code if needed:

XAML:

<Window x:Class="ClockApp.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
x:Name="MyWindow"
Title="Alarm Clock App" Height="180" Width="360" Visibility="Visible" ResizeMode="NoResize" WindowStyle="ToolWindow">

[Code] ....