(DM Note) Warfare

First start off with initiatives. Have the following roll for turns: Melee enemy, Ranged enemy, Melee allied, Ranged allied. Initiative= 10 + unit morale rating+commander’s Charisma modifier
The attackers start with a +4, the defenders start with a +2 morale. (can be raised to a +4 by a proper speech of the party).
https://media.wizards.com/2017/dnd/downloads/2017_UAMassCombat_MCUA_v1.pdf
Those on the wall have advantage.
Assign BRs!!! Based on the challange ratings of the ones making up the groups. Attacks are at advantage if together, disadvantage if the enemy is together.
Morale for the attackers is as above.
300 human fighters (barbarian leaders) with 4 ladders each (CR 1/8 (bandit) x 300 / 20 = BR 15) 100 Dwarf fighters with 2 battering rams ( hew Hackinstone, CR 2 * 100 = BR 100 ) 200 Drow and greyhawk (valley) high elven rangers. (replace these stat blocks) with 2 balistas each (Drow CR 1/4 * 200 / 10 = BR 20 )
On the scales side: 6 units manning 200 dragonborn each. Zisthik (White m db, wizard, 43 y/o), 200 casters) ( Center casters ) (apprentice wizard CR 1/4 * 200 = BR 20) Usnoth (Black f db, warlock 24 y/o, 200 fighters)) (Left) ( Guard CR 1/8 * 200 / 20 = BR 10) Dreso (Red m db, warlock, 28 y/o, 200 fighters) ( Right ) ( Guard CR 1/8 * 200 / 20 = BR 10) Recrund (Brass m db, warlock, 32 y/o, 200 casters) ( Wall right) (apprentice wizard CR 1/4 * 200 = BR 20) Olarys (Green m db, Ranger, 26 y/o, 200 fighters) ( Center front) ( Guard CR 1/8 * 200 / 20 = BR 10) Sarash (Gold f db, sorcerer 20 y/o, 200 casters) (Wall left) (apprentice wizard CR 1/4 * 200 = BR 20)
In short, caster BR 20, fighter BR 10.