trouble starting

I have the book and have downloaded the XCode compiler (I have a Mac) but I'm really having trouble getting started because the screens I see are nothing like those in the book. The book shows icons and I don't have them. I ran HelloWorld but it didn't run. apparently I haven't a 'signing certificate mac Development' but I don't know what that means.

It's probably easier to find help on a Mac/OSX specific forum, since this is mostly a language centric forum and many might not even have a Mac.

If you're just starting out and your book covers mostly small programs, you can keep yourself busy with online compilers like wandbox until you get help setting up your environment.