Officers are the highest grade in the U.S. Military. They are those who have joined the Military that have gone through College, and Officers Candidate School.
They hold authority over certain groups of men, and are usually non combat commanders.
They mainly rely on their NCOs to get their orders to the enlisted men. Some however would do it themselves such as Captain Winters during D-day and even dared to do so at Bastogne when he shouldn't have. Others who did this include Captain Spiers though as ordered to by Winters.
Some NCOs become Officers if they recieve a battlefield commision, and are taken off the line and sent to Officers Candidate School.
Their commands range from Platoons, to Companies, to Battalions, to Regiments, to Divisions, and in the 5 star Generals case, the entire Army.
The ranks range from Lieutenants (1st Lieutenant and 2nd Lieutenant) Captains, Majors, Lieutenant Colonels, Colonels, Brigadier Generals, Major Generals, Lieutenant Generals, Generals, and General of the Army.