Quick and easy: download and run this program (you will have to 'click through' a number of warnings about the risks of executing code you find on the web).
A virus-warning-free way is to download the Microsoft Keyboard Layout Creator (if that doesn't work, try this query. (You will need to have the .NET framework installed as well.)
Next, get a klc file from Johan's github and load it with the MS Keyboard Layout Creator (above). It has an option to make an excutable file - which is the program mentioned above.
The Windows version of AltGr-WEur is kindly provided by Johan Laenen.