Secrets of Xeria's Temple - Act 1 Side Quest
Location: Temple of Xeria
Closest Portal: The Temple of Xeria
Objective: Solve a block puzzle
Reward: Chant of Scholars & Loot/Gold
Secrets of Xeria's Temple is a Side Quest which begins in Eirulan by speaking with a Grizzled Bar Patron and listening to his very long story. For the first part of this quest you'll need to venture to the Temple of Xeria which is the final dungeon of Act 1. Inside of the Temple of Xeria there will be a room with some stones and sockets that resemble the Windstone Fortress puzzle you did just before accessing this temple.
This Side Quest will involve a puzzle that operates much the same way. You need to pick up the appropriately colored stones and put them into the right sockets. Doing this will open up a secret room for you with another pile of stones and more sockets. Rinse and repeat this process until you've opened up all 5 or 6 secret rooms in total and uncovered the Big Chest as well as the Lectern with the Chant of Scholars.
Explaining this puzzle to you would be more difficult than you actually completing it. Instead, let me give you a few tips as well as a link to my video of me doing the puzzle - which would be a better explanation than anything I can do here in text. Youtube video of me doing the Secrets of Xeria's Temple Puzzle
Tip: Pick up 3 or 4 of each color stone when you first encounter it - it'll save you a lot of time running around
Tip: Press Numpad 0 to make your party 'Wait' which will allow you to run around solo. It'll be less confusing without them following you from room to room.