It's quite simple. You can use video editing software like Adobe Premiere Pro or iMovie. Import your music video and the story footage, then combine them on the timeline.
First, pick a suitable music track. Then, in most video editing tools, there's an option to import both the videos and the music. You can sync the music to the mood and pace of your story by cutting and adjusting it. Some apps even have automatic music matching features that can help.
The stories in BTS' MVs usually combine elements of self-discovery, social issues, and personal growth. They use symbolic imagery and choreography to convey deep messages.
BTS music videos usually incorporate elements of their own experiences, as well as broader societal and cultural contexts. The inspiration can come from art, literature, and the members' own thoughts and feelings. They strive to convey powerful messages through visually captivating stories.