1. First, find the aerobics of the Red Dance Alliance in the browser, play it and make sure that the background music in the video is the background music to be downloaded. When playing a video, a URL will be generated in the address bar in the upper left corner of the browser. Right-click the URL and select Copy.

2. Open the used software, first set the software, click the audio icon, and then there are two options: video and audio. Because we are here to download the audio in the video, click here to select "Audio". Click "Paste Address" in the upper left corner of the interface, and the software will automatically detect and start downloading audio.

3. When downloading, the software interface will display the corresponding audio download progress. After downloading, the software will automatically convert the downloaded audio, and everything will be fine after the conversion is completed.