Problem with new header file

Every time i build Header file in Project  , and I already include some header file ( such as JuceHeader.h ) that i want to use in my new header file  . Why can't i still use any function or component from Juce Api ? .


Ps. i need to say that im so new with Xcode and c++ .


sorry, you're going to have to do a better job of explaining the problem for anyone to be able to help!