If you were placed in the position you have the military authority to direct and supervise all Soldiers under your charge.
In accordance with AR 600-20 paragraph 2-19 you should be senior to the individual by date of rank (DOR). If you are senior by date of rank the issue is cut and dry.
If however this individual is senior to you then TC 7-22.7 and aspects of AR 600-20 chapter 4 apply. As I stated above if you are placed in a position of authority to execute the duties of that position the Soldiers under your charge are resquired to follow your directives as long as they are legal, ethical, moral.