Where should the testng.xml file reside in a Java project in Netbeans IDE?

I am studying the TestNG framework with the purpose of using it more specifically with threads, since from what I saw in some websites, it is more efficient in this context (I accept suggestions of other possibilities), but it was not very clear to me where the ".xml" file in question should be inside the project so that I can run it through the IDE itself (in this case Netbeans IDE). Every help is welcome.