How to set up authorization via API in Swift?

Question

API

Hello dear! Briefly describe the situation: I relatively recently started learning Swift and decided to apply my resume for an internship. I was answered and given a test task in which I need to create an application authorization screen (already done). The screen itself is quite simple: in the center of the logo below there is some text and at the end there are 2 input fields (login, password,) and the "Login" button.

Now let's move on to the question:
I have a link to the authorization API (Postman), but I have no idea what to do with these. It seems that they asked me to make a simple authorization with subsequent exit for one user, but due to my inexperience, I cannot find the right solution on the Internet. I ask you for any help on this issue - articles / videos / your experience, whatever.