Change the opt-in settings via this option in the main menu:

From here you can customize various elements:

Select 'Instant Access' if you want people to access your resources without entering their contact information.

This is the form that will be shown when someone clicks on a resource in your library.

This is the email that will be sent to a subscriber after they enter their contact information.

Connect to your preferred email marketing tool so that new subscribers will be automatically added to your workflow.