I don't know what to do with an extension named microbit_UART1. When I try to use microbit_UART1.bluetoothdevice. Then something happens. Shows that I don't know how to use it. I try to connect to my microbit circuit using the bluetoothLE1 extension pack and it seems to be connected successfully, but I cannot send a string to the microbit circuit.
![image](https://community.appinventor.mit.edu/uploads/default/original/3X/c/4/c449b17184bf2aa12a03a14b9a9d706e16e9aa4b.png)