Then click "Insert → Background Music" on the third page to insert music, and an icon of background music will appear in the lower left corner of the slide. Then select it, right-click to edit the sound object, click the volume icon in the pop-up window, and then set the sound to mute.

The principle of this method is that when the slide switches to the third page, it will switch to the newly inserted background music. However, because the volume of the new background music is set to mute, it cannot be played, which has the effect of stopping playing the previous background music when it is played here.