First you need to split into 3 teams of 2. Step on the vex plates and start fighting off enemies. The door will eventually open and you need to go inside the vault of glass. Next there will be a big arena type thing and a "conflux" in the back middle. Kill the vex so none of them sacrifice themselves. It will say that the Templar Its summoning its legionaries and you just need to run around. Next two confluxes will spawn on the left and right. You need to do the same thing and defend them. It will say the legionaries are summoned and you need to run around. Now all 3 will spawn and you need to do what you have been doing. Now oracles will spawn and you need to kill all of them. Next a relic will spawn in the middle of the map. One person picks it up and starts to let it charge it's super. The relic holder needs to pop the Templar's shield with the super and every one needs to shoot it. Rinse and repeat until it's dead. Now you will need to go through a maze and not get seen by any enemies. The rest is to hard to explain so good luck on it