The steps to change the BMW music background image are as follows:

1. Open the BMW Music app: Find and open the BMW Music app on your device.

2. Enter the settings option: In the main interface or menu of the BMW Music application, there is usually a Settings or Profile option. Click to enter this option.

3. Find background settings: In the settings or profile interface, browse the different options to find settings related to the background. It may appear as "Background Image," "Theme," or something similar.

4. Change the background image: After entering the background setting options, there are usually several different background images to choose from. You can browse the list of images and select your favorite background image. Some apps also allow you to choose a custom image from your photo album as a background.

5. Apply new background image: After selecting your new background image, confirm your selection and save your settings. The BMW Music app will apply your new background image and display it on the app's interface.