Choose this model of the BlueFly if you want to connect to Android or iOS devices. Android devices connect using Bluetooth SPP. iOS devices connect using BLE. You can connect it to a Windows PC via USB to adjust settings.
This blog post provides more information on assembly of the BlueFlyVario_Bluetooth_USB_v22: https://blueflyvario.blogspot.com/2022/03/blueflyvariobluetooothusbv22-released.html
The package contains a fully assembled vario ready to go.