What does bands in art mean? what does characters in art mean?

Character, particularly when enacted by an actor in the theatre or cinema, involves "the illusion of being a human person". In literature, characters guide readers through their stories, helping them to understand plots and ponder themes.

Band in music, an ensemble of musicians playing chiefly woodwind, brass, and percussion instruments, in contradistinction to an orchestra, which contains stringed instruments. Apart from this specific designation, the word band has wide vernacular application, from generalized usage to the very specific.

the previous answer given.

i believe their role is to instruct certain sections on when they are to join and when they are to stop