In the side menu go to Data collection -> Feedback forms.
Select the New form button.
Name your feedback form and select the type of form. See ... for the differences between the form types Responsive Feedback Form for Web and In-App Mobile Feedback Form.
Select the CREATE FORM button.
You will start with an empty canvas.
Drag and drop the form elements into the canvas to include them in your form. See ... for a detailed overview of all the form builder elements.
Select DESIGN in the form builder menu.
Layout form builder.
Form builder menu
Form element menu
Form element options