Q:

Headers not finding files inside folders

I'm working with a nested project where I have a bunch of files inside folders; the problem comes when I import them.  I get an error saying File not found.  But if I type the name of the parent folder, slash and the file name everything seems to work OK.  So, I have to type #import "Folder/File.h" instead of #import "File.h".  I'm aware that there's an automatic way to do this. 
I assume that this issue can be solved by modifying some of the parameters on build phases.  But I'm not sure exactly what to do.  Could you give me any advice?  Thanks
Edit: This error only occurs when I do Archive.  When I do Build & Run I don't get any error.  

A:

Yes, you have to add that folder to 
USER_HEADER_SEARCH_PATHS

under the Build Settings Tab

A:

There is probably a more elegant way of doing that.  However, I typically solve that by adding the files to the xcode project. 