@Xperez You’ll need to edit your courses’ Schedules to make the available for enrollment. In Studio, go to Settings > Schedule & Details:
From there, you have two choices. You can adjust the course start date to be prior to today/now, and remove the end dates. For more info, see:
Alternatively, you can change your course to be self-paced, which sounds like what you’re describing here. You can only change the course pacing before the course start date, so if that has already passed, you’ll need to back-date it, save, and then you can change the pacing. More info on course pacing: