http – How do I simulate a website-login in iOS-app?

I wish to program an app that logs into an internet site with person/pw after which downloads some information from the web site (truly I simply wish to examine if a selected tag is current).
I am typically aware of app improvement (UI, information, and so forth.) however have by no means delved into “networking-stuff”, particularly not http.
In line with my analysis thus far, it ought to work as follows: 1. Look at the login-post request within the browser’s dev instruments. 2. Ship an post-request within the app 3. Watch for a response and obtain.
I can do step 3 for any web site, however I can not discover any tutorials/examples for steps 1 and a couple of (analyzing and performing the login-process) that specify it in a means I perceive. I do not know what phrases to search for both. Does any individual has any concept? A tough overview or only a few bullet factors would suffice.