That's why you have an IDE like Code Blocks

It allows you to create projects consisting from more than one source file. Therefore:
(1) Create a new project.
(2) Add both source files to the project. You can also add the header (recommended, the header will be at hand when you work on the project).
(3) In the Build Options - Compiler, tell the compiler where is your header.
(4) In the Build Options - Linker, inform the linker on additional libraries (if any).
(5) Save the project.
(6) Compile.
(7) Run or Debug.