Making Windows 11 use my custom keyboard layout

Hi,
I've created a custom keyboard layout for Windows. After running the dedicated installer, the relevant .dll appears in the Windows/System32/ folder.
However, I can't find a way to make Windows use it. From the system settings I can use the keyboard layouts supplied by Parallels, but not my custom one.
I know I could do it in the previous installation on a different Mac. But I don't know how I did it.
Paolo