In the next connecting room, there are a bunch of Data Monitors and maybe a couple of Team Galactic Employees.

One more floor up you will see the same thing, but with some cabinets available for looting.

Similar thing on the next floor, except this one has a bookshelf with a trial key in it.

Then the next floor changes it up. There is a bubble elevator. Ignore it for now, we will come back to it. Go through the iron door in the back.

Go down the hallway and you will find a gimmighoul.

Go back to the bubble elevator and take it up. You will find on this floor another gimmighoul and the Galactic Supervisor. You will then be able to take the bubble elevator down to another entrance.

In the adjacent room is a Team Galactic Scientist. The bookshelves on the back wall have a trial key somewhere in them.

Going up a floor, you will encounter another Team Galactic Scientist, but also a Team Galactic Researcher as well. Don't miss the Adamant Orb, you will need it to summon Dialga

On the next floor, there are a lot of distortion blocks and items. Feel free to takes these with you. Before going up the stairs, there is a hidden barrel one the side of the stairs.

On the next floor, you will come across what looks like a server room. There's a Team Galactic Engineer and a bubble elevator as well. Behind the servers on the left you can find a hidden barrel with a locator chip.

Going up the bubble elevator, you can find the Team Galactic Lab Director. Upon defeating him, he will drop some ominous trial keys. Try to put a waystone down so you can farm him for more ominous trial keys. Go down the other bubble elevator to go back and go through the middle entrance.

Coming into the main lobby, you will see a bubble elevator in the middle and 3 entrances, one on the left, one behind, and one on the right.

Inside you will find a gym, some lockers, and a restroom. There are no hidden barrels here.

Going back, we can now take the set of doors on the right. Immediately, you will see a bunch of stones on display and some pokedolls. At the back there are some fence gates behind a counter.

This is a mega meteoroid display room. If you turn around, there are some ladders you can climb to loot some chests on the top balcony.

Going up the bubble elevator, you will come across this room with a big chart in it. The left bookshelf (second image) contains some useful books.

Going up the stairs, you will find Saturn. Before you can fight him, you need to have already beat Jupiter in the Team Galactic Eterna Building. Beating Saturn will drop Valor Proof, which will lead you to Azelf.

When reaching the middle entrance, a similar dilemma is present. We will go through the left doors first.

Through the copper doors is a room with lots of honey. You will also find a Team Galactic Apiarits who upon defeat, drops more honey. Put a waystone here for easy honey farming.

Through the dark oak doors on the right is a giant library. The torches mark important books. The one on the left marks a Thank You book from the modpack creators and the one on the right marks a Torn Page. You should have 2 of these now since the first one came from Team Galactic Wind Plant.

If you pick up just the top middle book from the bookshelf that the soul torch is on, a secret entrance will open. Stand on the trapdoor, open it, then close it. You should be able to crawl now to the other end and find a bookshelf with the Torn Journal in it.

Upon entering the kitchen, you will see a bunch of cabinet's, freezers, and fridges you can loot.

Towards the back you may notice some black curtains. There are 2 layers of these you can pull back (right-click)

You will then enter some kind of toxic room. Here is a Team Galactic Garbageman who drops slimeballs and poisonous potatoes.

On the second floor is a similar thing, 6 dorms. Make sure to stay on the left side of the bubble elevator this time.

On the third floor we start seeing some fancy rooms. See image 2 as an example. Keep on looting. Stay on the right side when going up

On the fourth floor, we will see a large suite.

Going up one more floor, you will the largest and fanciest room. On the bookshelf that has the torch behind it, you should be able to the last Torn Page needed to craft the Old Journal.

You will come across a large arena. There is a chest behind the blue chair. Don't forget to steal the Power Spots. They foreshadow what Cyrus will bring (unless both are removed and were not placed before the battle began).

After beating Cyrus, he will drop the Red Chain. Finally, you are done with the Team Galactic HQ and can now go summon Palkia and Dialga.