There are many ways to do this fight and basically it is like this:
Do you have good dps?
-try 2 tanks 2 heals 6 dps.
A: if you manage to kill the tentacle before the meteor comes then you are golden.
if A is not possible all the time, then you might want to drop a tank for a dps like the above poster did so that you are certains to
1: kill the tentacle before it could cast a second empale
2: kill tentacle before missile arrives
3: easily burst missile and adds.
Then for the order it is really simple:
1: keep the "keeper of time" for last if you do not have CDs to survive the meteor, otherwise kill it in 3rd
2: if you have just one tank you might want to keep the green boss until last so that the tank has an extra CD
3: if you are playing with 7 dps you should not have issues with dps, if you have, then you leave the blue dragon for 20% extra damage for last.
So what is the order?
Green -> red -> yellow for time -> blue
When you reach blue, you want to make sure to call out for the missile and use two CDs for the raid: tank CD and aura mastery for example.
Good luck