First you will need to access your website editor. If you don't know how to do so, you can read this article
Next, you will need to access your front page editor. If you don't now how to do so, you can read this article
To Add Widgets, once you are on the front page editor, you will select the "+Add Widget" button as shown in the picture below
After you’ve clicked “+Add Widget” a new window will pop up where you can choose from a variety of widgets including Forms, Calculators and Testimonials.
Once you have chosen the widget that you would like to add to your website it will appear at the bottom of the page as shown in the following image
From here, you can click and drag the widget to the desired spot (i.e moving to the top will move the widget to the top of your front page).
Once you have moved the widget to your desired location, on the right side of the website you will press the "Update" button to finalize these changes.