The steps for plugging in the Bluetooth adapter of Xiangyu to connect to the Bluetooth speaker are as follows:

1. Insert the Bluetooth adapter of Xiangyu into the USB interface of the computer. The computer will automatically recognize and install the driver.

2. Open the Bluetooth settings interface of the computer and enable the Bluetooth function. Under Windows systems, you can find the "Devices" option in "Settings", click "Bluetooth and other devices" to enter the Bluetooth settings interface, and Under Mac system, you can find the "Bluetooth" option in "System Preferences" to enable the Bluetooth function.

3. Turn on the Bluetooth speaker and make sure it is searchable. Normally, the Bluetooth speaker will automatically enter the searchable state when it is turned on. You can also press and hold the Bluetooth pairing button on the speaker to enter the search state.

4. Search for connectable Bluetooth devices in the Bluetooth settings interface of the computer, find the Bluetooth speaker and click to connect.

5. If the Bluetooth speaker requires a pairing code, enter the corresponding pairing code on the computer.

6. Wait for the computer and Bluetooth speaker to be paired successfully. After the connection is completed, you can start using the Bluetooth speaker to play music.