Instructions
Locate the perk machines.
Station one player at each of the machines to fend off the monkeys as they attack the machine to steal your perks. Monkeys only go after machines if someone in your party purchased the perk.
Kill the zombies as they come at you. If you get knocked down even once your perks go with you. A member of your team can bring you back up but you'll lose your perks, so be extra vigilant in blocking all entrances to zombies and position yourself so you cannot be attacked from multiple directions.
Work in pairs. It's always better to stick close to your teammates so you can watch each other's backs.