I am very new to developing IOS games, but have published my first game into the appstore (it was just a very simple dice game like yhatzee using SpriteKit and it has a high-score saved by using NSUserDefaults)

Doing that taught me a lot, and I am eager to start a new project or add onto the capabilities of the app I just published. But, I am feeling very lost when it comes to Game Center & leaderboards as it is quite daunting.

There isn’t many up-to-date resources I could find on integrating Game Center & leaderboards as a lot of old resources used deprecated language

• How can I let the user log into GameCenter?
• How can I also have a leaderboard of like the top 15 people and their high-scores (kind of like subway surfers and how they have their “top runs” leaderboard)?

I know this question is quite broad, but does anyone have any recommendations on how I can implement this functionality or any resources that can help me learn and understand??

I tried adding the GameCenter capability to a X-Code project, and then registering the app on my App Store Connect with GameCenter enabled.
Then I added a classic leaderboard there.
Then back in X-Code, I tried doing all these different ways of letting the user log into game center and trying to access the leaderboard via its ID but to no avail because all my references used deprecated language.