custom language support tutorial

I've followed the custom language support tutorial without success https://www.jetbrains.org/intellij/sdk/docs/tutorials/custom_language_support_tutorial.html . I'm running IntelliJ Community 19.2.2 and have tried both variants of step 2.5 https://www.jetbrains.org/intellij/sdk/docs/tutorials/custom_language_support/language_and_filetype.html but IntelliJ still asks for a file type to associate test.simple with.  Any ideas what I can check on?