Five-field cron, in UTC
The cron helper explains minute, hour, day of month, month, and day of week. It does not install a job.
The expression has five fields. Names such as MON and JAN are accepted. Sunday is 0 or 7. Steps and lists work, as in */15 or 1,15.
Times are calculated in UTC. When both the day-of-month and day-of-week fields are restricted, a date matches if either field matches. That is the usual cron rule, and the description says so when it applies.
A six-field expression that includes seconds is rejected. Quartz-style year fields are rejected too. Copy the five fields into the scheduler you actually run, and confirm that scheduler's timezone separately.