Common verb-object compound that often splits: 报一个班 ('sign up for a class'), 报英语班 ('sign up for English class'). The 班 here is a 'class / training cohort,' not a 'shift' as in 上班.
culture
Closely tied to Chinese 课外班 ('after-school class') culture - until the 2021 双减 ('double reduction') policy, urban families spent heavily on 报班 for kids' academics, music, art, and sports.