This figure shows the Test NXSD Schema dialog. This page has the following text:

Provide a native file and click Run to generate the runtime xml document.

Below this text is the File name field with address-csv.txt entered as the file name. Below this, the content of the address-csv.txt file is organized as records. Below this is the Schema and the Result XML pane and a Run icon. The Schema pane is populated with the schema file.