To create costumes for their music video that would appeal to their target audience of 13-24 year olds, the document discusses researching the fashion styles of that age group on social media. It describes choosing a checked shirt for the male actor that symbolizes romance, as well as jeans and a floral top for the actors that would be casual outfits for a park visit. The document also notes keeping the musician in trademark clothes like at concerts to establish his persona for new fans.