How do I use iMac as second display for MacBook Air
I use my 2011 27-inch iMac as the display for my MacBook Air 2018 by connecting iMac mini-display port to MacBook Thunderbolt port, and typing Command-Fn2 on the iMac. Now I want to use my Apple Bluetooth keyboard with the MacBook Air. How do I get MacBook Air to connect to the iMac's bluetooth keyboard?
MacBook Air 13″, macOS 11.2