iMac as a second display
How do I get my late 2012 iMac to work as a second monitor, when it's running os 10.15.7 Catalina, and my 2019 macbook pro is running big sur? I've purchased both the Thunderbolt 3 (USB-C) to Thunderbolt 2 adapter and the Thunderbolt Cable. I've restarted, tried detecting for other displays and nothing seems to work.