This is "unresolved external symbol" error. Too bad you did not report exact and complete error message; you should always do it. The reason is: you use some object code created by a compiler, without the source code. This code can be available in the form of either object file (*.obj) or, more likely, object library (*.lib). The task of the linker is to take all object codes together (those were just compiled from your source code and those from the libraries), put them together, and resolve all dependencies between them by the names of methods and variables.
You use the interface of this code through a header file, but did not supply the library itself. It's done by the command line options of the linker or through the propertied of your project. You need to 1) read complete error message and find out what symbol is not resolved, 2) identify by, say, header files, what library this symbol belongs too and identify this library; 3) find out where the library *.lib file (or *.obj files) is located and add it to the project.
Please be careful: the linker symbol could differ from the source-code name of it due to the name mangling: