xcode 101 - import file question

Question

when importing a file, what does "Copy items into destination group’s folder (if needed)" mean?

Answer 1

That means if you add files to a group, that is bound to the folder

~/Project/Test

and the file is in that folder

~/Project/Test/SomeFile.m

the file is just added to the Xcode project list. But if the file is elsewhere on your disk, it is first copied to this folder and then added to the Xcode list. If you don't check that, the file is never copied, no matter where it is located, Xcode refers to this file at its current location.