the first matches had started, just not the atp matches. Does this mean that I'm required to scoreboard watch from the scheduled start time to whenever the atp matches actually start? for each day of the tournament?
yes, just to mark the start of men's play. the second possible way is calculate the starting time assuming the elapsed time of the first match. and third method is to assume 10 minutes after the play started, if no rain. also some other players, who are online, are marking people, who are late.