Usage patterns
〈人〉が部下を持つto have subordinates (under one's supervision)
He has ten subordinates under him.
部下に〈事〉を指示するto instruct one's subordinates to do something
The section chief instructed his subordinates on the new task.
部下を指導するto guide or train one's subordinates
She carefully trains her new subordinates.
部下の相談に乗るto listen to and advise a subordinate on their concerns
My boss listened to my concerns as a subordinate.
Expressions
腹心の部下trusted subordinate; right-hand man; henchman