Adding a Button or Other Widgets
Widgets - such as Buttons - are the items with which you trigger actions and display information. Adding them is fairly easy.
What you have to do:
Start the edit mode by clicking on the edit button in the left drawer.
Four new buttons appear in the lower left area. To add a Button Widget, click on the left icon. If you want to add other widgets (Seekbars, WebViews, ...), click on the second icon. You can then choose which Widget to add.
The widget appears. You have to press and hold it, then drag it to the position where you want it to be. Don't worry, you can easily change the position later.
After dragging your widget, its properties automatically open. Choose the design, actions, text, icon and so on. Then leave the properties. Your Widget has been added.