Clearly indicate what is expected which you did well.
Do not forget that you need to follow up: e.g. always associate a task with a timeline, you can ask the peron what kind of time frame she/he can deliver the result or give this person a deadline. Contact this person when the deadline is approaching, skillfully ask whether she/he needs additional support to meet the time line. In this way, you will be able to turn the table round: if there is no delivery at the timeline which she/he agreed upon, it will be an performance issue on her/his records. You will be able to take it further. But, most of time, with a designated task to specific person and a timeline, the person will delivery what you asked.
Good luck,
