Info on the in game club challenge we've been playing an completing but what is the secret journal..

Info on the in game club challenge we've been playing an completing but what is the secret journal for they haven't gotten around to using that yet an not quite sure why adding more clue tokens to get an no more rewards for doing more Not Nice! An one of members is having trouble getting into challenge I've sent invite an they show up on board with other club members but they can't play. They just left another team challenge to join our club maybe that's why but hasn't happen before usually player accepts an joins challenge. Thanks for any help