Help with coop mission

[chocolatestar 10]

Hi guys.

Currently making a mission, my first which is why i'm noob.

Ok.

There are 6 navy seals, the objective is to go to the ammo box (about 500m below camp tempest) , resupply from the shitty UW Weapon (you start in the sea).

After this you go to camp tempest, eliminate any insurgents (they don't all need to be killed), but you need to destroy the 3 ammo boxes around camp tempest.

now, i've placed the ammo boxes around. I've also made triggers for each one, which include

condition - !alive cache

hint "The enemy ammo cache has been eliminated!";

i've applied this to each one, naming each one with numerals.

How do I make the objectives to destroy this ammo box and rendezvous at the extraction point which will eventually win the game?

Thanks.

Chocolatestar