@Evan_Moffatthow do stands and solos interact? Should a solo seem just as powerful as 10 comparable CR creatures? Yes – the idea is that a solo is a notable figure who has a big effect on the battle – Aragorn or Legolas in the LOTR movies.
— Mike Mearls (@mikemearls) March 2, 2015
Sage Advice: you can download Mass Combat Rules for Dungeons&Dragons here