Visual Studio Code – What is WinMain and how does it work in c

I’m trying to learn C, and I’m stuck right at the beginning. To my knowledge, WinMain is the entry point to a GUI application in C. I’m running into issues trying to get it to work. This is the code I’m trying to run

#include <windows.h>

void foo(void) {
    OutputDebugStringA("This is the first thing we have actually printed.n");
}
int CALLBACK WinMain(
     HINSTANCE hInstance,
     HINSTANCE hPrevInstance,
     LPSTR     lpCmdLine,
     int       nShowCmd
)
{
    foo();
}

These are the corresponding errors

C29251- Inconsistent annotation for ‘WinMain’: this instance has no
annotations. See c:/filepath

LNK1120- 1 unresolved externals

LNK2019- Unresolved symbol main referenced in function "int_cdecl
invoke_main(void)(?invoke_main@YAHXZ)

I’ve read through
https://learn.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-winmain

I’ve tried the two separate code snippets provided, and neither ran on my computer.

I’m using Visual Studio