I followed the instructions as per that page. Used "download" link for OpenJDK11, "Android SDK Command line tools" link for android sdk and "required resources" link for the additional components. The only difference is I created a B4A folder into which everything was unzipped to and the java folder is "Java" ie capital "J" not that I think that makes any difference. B4A was installed to the Program File (x86) folder. Thanks.