Protect Pro and Alarm Monitoring confusion

Ring is making it extremely difficult to get alarm monitoring. Protect Pro is advertized as including alarm monitoring. When I signed up for Protect Pro, I get a message saying "Alarm Professional Monitoring isn't available at this location." After hours in chat with Ring, I found this message is misleading. They mean to say "You don't yet have devices to enable alarm monitoring." The question is what devices do I need? I have 2 Ring door cameras. Ring cannot show me anything on their website that helps. I am looking for a step by step plan to get Ring alarm monitoring. What do I need to do?