Stilshrine of Miriam map (

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Look at the map I linked you. When you first enter the area, equip the Dawn Shard to your party leader(his/her MP would go down to 0), and then touch the Pedestal of the Dawn. Then you would be teleported to an area called "Ward of Vetilation". There would be monsters appearing so watch out for that!
Then go to the next area called "Walk of Torn Illusion". Climb the first staircase then defeat the Miriam Facer at the top. Then just go either side of the side stairs and fight through the Miriam Guardians to another Pedestal of the Dawn. Equip the Dawn Shard(if you removed it) then activate the pedestal to unlock two hidden staircases back in the Ward of Velitation. Go either side of the unlocked stairs which will lead you to an area called "Walk of Revelation".
This room has a green save crystal, which is actually an enemy. Touch it, and then defeat it and then a real blue save crystal will appear. Save here if you want.
Go to the next area called "Ward of the Sword King". Some more monsters appear so watch out for them. Go south and examine the massive stone Sword of Judgment that is blocking your path. That will unlock the door to the north side which leads to a way stone. Touch the way stone and teleport back to where you started. You can remove the Dawn Shard now if you want.
See the stairways on either side of the area where you began? Those are unlocked now. Go to either side of them. Look at the linked map above. See those yellow arrows? That's the way you need the three statues to be facing. If you go to the east side statue, there's going to be a boss battle there. So be ready for that. The other way are pretty linear. Hack your way through monsters and find the statue and make sure they're all facing the right way(facing the massive statue in the middle of the first area).
After that, teleport again to the Ward of Sword King, and you can go to the area that big sword was blocking before, and make your way to there and be ready to fight the esper Mateus.