The Eyes of Sauron, Shadows of the Past and The Seeing Stone are three missions as part of the Gondor storyline in Middle-earth: Shadow of War.
These unlock one after another, and come after completing The Gondor Prologue and Fellowship quests.
If you are interested in completing other missions in the game, our Shadow of War guide and walkthrough can help.
The Eyes of Sauron
Mark the location on your map, climb up to it, activate the Haedir when prompted, and use it to mark items of interest on the map.
Shadows of the Past
Reward: Bronze: 500 Mirian, Silver: Skill point, Gold: Wealth stone.
Find Celebrimbor's Ancient Barrows: Head into the cave then use your Wraith abilities to open the door.
Build the Power of the Ring: Kill Orcs as quickly as you can - concentrate on the smaller ones if possible.
Unleash the Power of the Ring: Follow the onscreen prompt to activate Elven Rage, then move around the area mashing your attack button.
The Seeing Stone
Reward: 1800 XP, 355 Mirian
Bonus objective: 100 Mirian
Defend the Gate: Follow Idril, and take out a few Orcs when you arrive at your destination. Someone's chucking huge rocks at you, so try and keep clear of the blast radius by avoiding the large red circles on the ground.
Follow Idril, Disable the Siege Beast: Shoot arrows at the pale blue areas on the Siege Beast.
Need more help? Our Shadow of War guide and walkthrough gives you an overview of everything you need, but if you need something in particular, we have pages on Shadow of War Fortress Sieges, how to earn Mirian in Shadow of War, a guide for how to import your Nemesis and Follower to Shadow of War, collectibles guides like how to get all Shadow of War Legendary Armour and Weapons sets, a list of Lost Artifacts and Web of Fate locations, and Ithildin Door poem solutions and Shadows of the Past, along with how to grind XP in Shadow of War to power through the tricky Shadow Wars endgame and get the true ending. Finally, there's Shadow of War's army building explained and the best skills and how to earn Skill Points.
Mount the Siege Beast: Make your way to the Beast, then follow the onscreen prompts to climb onto it.
Destroy the Assaulting Forces / Destroy the Enemy Siege Beast: Fire rocks at the Orcs scurrying below, then unleash a couple at the Siege Beast to the south west.
Reach the Next Siege Beast: You now have a double jump ability, so use that to help you cross the city to your destination. (Reaching it before the timer runs out will earn a bonus 100 Mirian.)
Disable the Siege Beast / Mount the Siege Beast.
Destroy the Assaulting Forces / Destroy the Enemy Siege Beasts: Rain down more fiery mayhem on your foes.