Hi In Unit 5 “Bluetooth Classic”, I am unclear why there is no link to download and install the library BluetoothSerial.h. How was it installed? I don’t see it in the Arduino IDE libraries.
I’m sorry for taking so long to get back to you.
That library is installed by default when you install the ESP32 boards.
But, are you getting any compilation error because of the library?
To see its examples, you must have an ESP32 board selected in the Boards menu.