Hi Delyoesz!
The first thing has came to my mind is to prepare a CSV file for creating this enrolments manually: https://docs.moodle.org/en/Bulk_enrolments (after first load, you'll need to add new users manually).
If you're planning to add more courses with this behaviour, I would recomend you to create cohorts instead and use the cohort sync enrolment method: https://docs.moodle.org/en/Cohorts#Adding_users_to_a_cohort_in_bulk
Hope this helps!
Sara