Hi @tanckom,
I hope you are well today and thank you for your question.
You can achieve this by creating Download / Media Protected groups from the following path. By default the default protected group is created.
Admin area -> Membership -> Options -> Download / Media tab -> Protected groups
From the media library attach the files to the respective Protected groups then create access level and use the Downloads access level rules in it selecting the protected group so that the files belonging to these groups will be secured for the non subscribers.
Create new subscription plan and use the created access level in it.
Now the users not subscribed to the created subscription plan won’t be able to access the secured files.
Please advise if you have more questions.
Cheers,
WPMU DEV