Explain in detail Kant’s notion of the first formulation of the categorical impe

Explain in detail Kant’s notion of the first formulation of the categorical imperative, how it is the basis of doing one’s duty as opposed to acting on one’s inclinations, how rationality is the cornerstone of the categorical imperative, and why Kant says a person is morally autonomous. Use the following as the framework for answering this exam question; according to Kant, why can’t one say, “I can lie whenever it’s in my interest to do so?”