Click on the Widgets tab (1) and you should be able to see the Button widget on the right (2).
Select the Button widget and drag it to your page (1)
Click on the widget so you can see the settings menu on the left.
1. Click on the Lin to... button to create a link for it.
2. Select an icon for your button
3. Change the title of the button and set up the style.
4. Aligne the button
5. Don't forget to save your changes when you finish
Copy the widget
When you Copy (1) a widget, the widget will be saved on the top right of your site. Go to another page and drag the copied item (2) to your page.