Step 1 - In your Customizer, click on the Widgets tab
Step 2 - To add a widget, first click on a widget area. In the panel, click on Add a Widget. The Customizer will show all of the available widgets that you can add.
Step 3 - Now click on a widget to add it. The Customizer will then display a box to configure the widget’s settings.
Step 4 - Once you have updated the necessary fields, click Close on the bottom left of the widget box.