You can add extra buttons to your LeadForms by dragging and dropping the button from the "Add" section on the Customiser step, wherever you would like the button to appear.
You have three different options for buttons that you can add, Next, Previous or Link. These options are displayed in the drop-down field inside the popup that appears when you add the button to your LeadForm.
Previous button: will allow your users to return to the previous step in your form.
Next button: will only be an option if you have deleted the default next button from your form, this then allows you to add it back again.
Link button: will allow you to add a button that will link to any URL that you add to the button.