How to use OAuth API

Hi, I am very new to making apps and had a question about using APIs.

I want to develop an app using the animal data found on the PetFinder API. This API uses OAuth for secure authentication, and requests to receive JSON begin with a cURL -H command, which I don’t have any experience with.

The specifics of the API can be found here:

I know for other APIs you can make calls to a url with your key. But how do I implement these authentication requests in Xcode and Swift in order to recieve the JSON for my app. Appreciate any help I can get and thanks in advance!

Maybe check the sample code (project) provided in the api to see how they make the call themselves