I finished entered all the codes correctly You don't show code, it is hard to say. But the problem could be that you have created a recursive call, causing infinite loop that finally exceed system resources. We would need to see the code to confirm this hypothesis.

I'm still unsure about a lot of things. The best way to use this forum is to ask questions, one by one. If you do so, don't forget to post the relevant piece of code and explain clearly what doesn't work as expected or what you don't understand. Note: could you post the link to the WWDC21 session ?

This is only a reminder of Apple's guidelines. What is your question ? Have you done what is required here ?

gives me an unrecognized selector error Which line ? You need to retrieve the item, which is the selected cell. You can do this in didSelectRow to keep the selectedCell reference. Or you could also extract there item.yahooName and keep it in a var selectedName in VC and use it in prepare.

Another point: don't force downcast. If it fails, app will crash   let destinationController = segue.destination as! HighlightsVC       destinationController.playerName = (item.yahooName!) But conditionnal unwrap: if  let destinationController = segue.destination as? HighlightsVC {       destinationController.playerName = selectedName // Set in didSelectRow } No need either for parenthesis around name, but for such code, use ?? operator:       destinationController.playerName = item.yahooName ?? ""

When you open API documentation in Xcode, it does open on Swift version if you have a Swift app. it always shows it in Objective-C,  No, not what I get. When you open in Safari, it depends how you searched for. Could you detail the scenario that causes you this (small) problem ?

The thing is I don't want the whole cell to be selected. I just want the button to be. When you tap the button, de facto you select cell. So probably you can use optional func tableView(_ tableView: UITableView, willSelectRowAt indexPath: IndexPath) -> IndexPath? to get the select and immediately deselect it so that it is not highlighted. But in the meantime, get the cell reference and name.

what you mean by cell reference In willSelectRowAt, you can either get the cell itself or you can directly get the yahooName of the cell. And save it in a global var of the VC. Then, the segue is from the VC (not the cell) to the next VC. In prepare, you set the name as you have done. In IBAction, just call the segue: @IBAction func CamButtonA(_ sender: UIButton) {           performSegue(withIdentifier: "hs", sender: nil) // No need to know the sender here }

Why don't you download an older version of XCode ? If it is just to learn Swift, it will let you start…

What is it more precisely you don't understand ? It it the for loop, the while loop ? Is it something specific in the syntax ? Please give examples of what you don't understand, we'll try to help. Note: you should use Apple book: intro to App development with Swift or, more detailed: The Swift programming language. They are much more didactic and will ease your understanding.

I do not see a stackView in tour set up, to be included in the scrollView.

As OOPer explained, it will fail. It is not a question of size. However, if you subclass MyPeg class MySubPeg : MyPeg { var sub = "hello" } Then test will succeed.

You can't put any segues in there. What is the problem ? Do you get an error message ? Did you create the segue between VC (not cell) and the destination ?

This could provide you some information or links for further investigation. My understanding is that this is a harmless message. https://stackoverflow.com/questions/10109367/should-i-worry-about-a-scoped-bookmarks-agent-connection-interrupted-log-messa

That should work. Which version of Xcode ? Could you test with : Swift.print(greeting) And tell what you get ? Check also in Xcode Preferences, in case you have set a white font for the console: Otherwise, could you attach the full playground project so that one can investigate ?