Hooking messageboxa using a DLL

See more:

C++

DLL

MessageBox

hooking

I've recently created a "hello world" c++ program:

#include <windows.h>

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd)
{
    MessageBoxA(NULL, "Hello World!", "", MB_OK);
    return 0;
}

What I need to do now is create a dll that hooks MessageBoxA API and changes the message (I want to load the dll from my main program using LoadLibrary).

I've downloaded and properly installed MS Detours 3.0 and have searched the web for help, but I'm completely stuck! Any help would be appreciated in creating that dll.

Thanks in advance.

What I have tried:

Searching the web and trying everything I found.