Add the library project to your workspace or project. Add the library scheme (NSPredicateDictionary) to the Build portion of your scheme. Make the library product (libNSPredicateDictionary.a) a dependancy of your target. Link against the library.
Import the header in the classes that use it:
#import <NSPredicateDictionary/NSPredicateDictionary.h>
Make sure your project has the "Other Linker Flag" "-all_load" set. See Technical Q&A QA1490 for an explanation of why.
See the included HTTP REST service sample code, QUELLRestServicePredicate.
This functionality is implemented as an informal protocol on the Foundation NSPredicate classes. Apple requests that when extending Foundation classes a prefix should be added.