Compared to the general English word “explain,” 解说 has a more specific, performance-oriented connotation. You might “explain” a math problem to a friend one-on-one, which would be 解释 (jiěshì). But when you are systematically walking an audience through a process or event as it happens, you are doing 解说. This reflects a cultural appreciation for structured, expert-led interpretation, where a knowledgeable figure guides the layman through a complex experience, whether it's a piece of art, a political event, or a soccer match.