Can you use Oauth to access Instagram API?

I’ve been trying to figure out how exactly Instagram API works and want to try creating my own authentication/authorization tokens to access their APIs.

Does anyone know whether it’s possible to do so using Oauth? From my limited understanding, Instagram has both, an official and an unofficial API. Could someone please enlighten me as to how one can even navigate the undocumented one? How do you know where to send the requests to?