In order to ride an Elite Turbo Muin, you'll need some external sensors for Zwift to read from it. The good news is that Elite makes two compatible models!
Securing either one of these sensors will set your Turbo Muin to transmit data (if you're unsure how to attach the sensor, please contact Elite). From there, depending on which sensor you're using, you have a couple different options.
The Misuro B+ actually transmits both speed and power data, so you can search for it under either the Speed menu - and then select the Elite Turbo Muin Fluid - or under the Power menu, and select it as a power source.
Cad/Speed Sensor ANT+, 20 Cm
The Cad/Speed sensor only transmits speed data, so you'll search for it under the Speed menu and select the Elite Turbo Muin.
You can then choose to pair Cadence.