Ragnarok (Disc 3)
The first thing you should do is save – obviously! Who wants to go through that much story again…
Enter through the doorway and into the airlock room. After a bit more talking you can walk through the closest door to find out that Propagators (the aliens wandering around) already occupy the Ragnarok. Make sure that you have fully junctioned Rinoa and Squall before you accidentally wander into any fights.
The premise to fighting the Propagators is quite simple. Each color of propagator comes in a pair. In order to defeat the two propagators you have to kill two of the same color before killing any others. In other words, killing purple and then the other purple will destroy them both. If you kill purple, then red, then purple again both of the purple Propagators will come back.
The Propagators are not too tough to defeat so do not fret over a fighting strategy for these monsters. They are not immune to Sleep magic, so equipping Sleep to your Status Attack junction is a very good idea.
Start by walking down the stairs to the right of the screen to fight the purple Propagator you just saw. Head north (through the large door, not the small one) into the next room but be careful of the red Propagator that is about to come running at you. You want to quickly run forward and to the left into the next room before the red Propagator touches you. The second purple Propagator is in this room.
Now go back to the previous room and kill the red Propagator. Go back into the room where you killed the second purple Propagator (noticing of course that it is now gone) and head left one more time. Ignore the green Propagator and head straight towards the screen to find the red Propagator in the next room. Both of those two are now done.
Go back into the previous room and kill the green Propagator that was just standing there all nonchalant-like. Go back to the room with the second red Propagator (and do not forget to grab the Life draw point) and then head down the stairs on the right. You should find yourself back in the room where you killed the first purple Propagator.
Walk through the tiny door to the right of the large one you walked through before and kill the second green Propagator. Save if you would like to. Head back out to where you killed the first purple Propagator and head up the stairs. Head back towards where you entered the ship to find a yellow Propagator (and fight it). Now go north past the draw point and north again to fight the very last yellow Propagator.
Note that this last Propagator is, shall we say, angry with you killing all of his buddies. He hits slightly harder and faster than the previous ones you have fought. The last yellow Propagator pushes you out of the room so you should already be in the correct room – ride the elevator in the middle of the room up to the cockpit.
The Ragnarok is now yours! (After some cheesy story of course…) Walk into the passenger area (not the cockpit) after all of the talking is done and the rest of your team will join you.
Tons of stuff you can do now but there are a few parts of the story that should be wrapped up before hand.