Header files simply tell the Compiler not to worry that the function isn’t actually defined in the current source file; they promise the Compiler that the function be will provided from some other source external to the current source file - usually another source file, or a Library.
So the compiler accepts this promise, and generates an Object file that requires these functions to be provided externally.
It is the Linker’s job to fulfil the promise…
Those are Linker errors - hence the “LNK” prefix.
The Linker is telling you that the Object file appli.obj requires these functions to be provided externally, but it (the Linker) cannot find anything to fulfil that requirement.
This presumably means that you haven’t correctly configured your application to include the actual WIP Libraries - you need to check using the Project Wizard.