Jessie, this is a great question.
I would have started with asking the managers to give you a detailed plan before you went out to hire interns, but it's not too late. Ask managers for a list of tasks for each intern, then set up weekly appointments where the interns give you feedback about the job. It only has to be a 5-10 minute meeting unless the chat reveals a problem.
The meetings serve two purposes: to remind managers not to dump menial chores on interns, and to help interns feel heard, included and valued.
Hope this helps!