You can start this mission from a Rakyat guy in front of the temple that is northeast of Citra’s Temple. He wants to restore the temples, but needs you to find some tablets. There are three of these tablets and you aren’t given the exact locations. When you get to each objective marker, a general area of where the tablet is located is highlighted in blue.
For the first tablet, go inside of the temple. Once inside, head to the left and find the water that leads down to where Relic #56 is/was located. At the bottom of the stairs and a little to the right should be the tablet, so pick it up. For the second tablet, head back outside and to the closest marker. Find the tall structure and you’ll see the second tablet on the ground, leaning up against one of the pillars.
The third, and final, tablet is located to the south, so head in that direction. Once you get to the temple, head up the stairs on the right side and climb up to the ledge. Use some kind of explosives to blast open the stone door, but don’t climb the ladder when you cross the bridge. Shimmy around the ledge and go behind the ladder to find the tablet. Once you have them all, head back to the man to finish this mission, earning $500.