Custom Template not showing

Hello, I have looked at the documentation and I have seen that it is necessary to create a directory called ‘download-monitor’ in the active theme. I have created it and added content-download-box.php with some modifications, I have also changed the name, but I can’t get it to show it in my posts.
Is it an extension that must be acquired or is it possible from the free version?

I use the Download Button block, select Custom template and type content-download-box2 but it shows the default template.

I have also used
[download id = “1” template = “content-download-box2”]
And nothing ??

Is this how it is done?
Is there documentation to investigate further?
Thank you