I don't use DevPaks, but I guess they contain the necessary things nevertheless.
What you need is the header file placed in the GL folder, and
libglfw.a in a place where your linker will find it (for example
C:\codeblocks\lib). I assume you have the path added to your linker directories.
In the rare case that you want to link to GLFW
dynamically (which is pretty much nonsense given its small size, but possible nevertheless), the linker needs
libglfwdll.a and
glfw.dll too.
Your project must contain the following libraries:
glfw,
opengl32,
glu32,
gdi32,
user32, and
kernel32.
Instead of using the DevPak, you can also build GLFW from sources, this takes about 2 minutes alltogether, so it may very well be worth it. Following the WiKi works reliably.