General army structure:
Squad --> 8-12 men, commanded by a Sergeant.
Platoon --> 3-5 squads, commanded by a (2nd)\Lieutenant.
Company --> 3-5 Platoons, commanded by Captain
Regiment --> 3-4 Platoons, commanded by a Major/Lt. Col.
Battalion --> 3-4 Regiments, commanded by a Col.
Brigade --> 3-4 battalions, commanded by a Brigadier General
Division --> 3-4 Brigades, commanded by a Major General
Core --> entire branch of service. Commanded by a Lt. Gen.
Army --> All forces availeable at a theatre of operations - commanded by a General.