Changing the form

[KaGeRo]

In my installation it`s 2 licenses, and in second one, you may agree or disagree. So I want to make a form, with four buttons("Back", "I Accept", "I Decline" and "Cancel").

I`m a new in using NSIS, but I want to know, how can I change form, so that it includes 4 buttons (instead of 3 buttons) in my own form?

Thanks in advance...