Conqueror helps you with the spellvamp very very much. You will see that he is gaining a lot of health and some items can increase a lot. In the team-fights he will be unkillable and you will be the MVP from all of them. As, you know Conqueror has made for bruisers so it's made for him.
Press the Attack is better to 1vs1 fights, that means that is better during the lane phase. you can take Press the Attack against an late-game champion to bully him during early-game. Press the Attack is also good at split-pushing.
What are you going to take is your choice according the match up and your play style.

Triumph gives health when you take a takedown (kill or/and assist) and also gives you 20 golds per takedown. This is the best rune of the three since you don't have that big need of mana to take Presence of Mind but if you you waste a lot of mana you can take but i say again that Triumph is the best. you don't need Overheal you have spellvamp so you have abilities to heal.
since when your damage some from hits and you have ability that increase your attack speed you take attack speed. You can take also Legend: Tenacity if they have many cc like Leona or Maokai.
You can outplay players when you are low so take Last Stand. We take this also to champions that have abilities to heal like Warwick.

Take Taste of Blood to make greater your spellvamp. You don't need Sudden Impact since you have no dash and you need Cheap Shot either because you don't need that lethality.
Relentless Hunter you take this because you need movement speed to catch enemies with your q. If your build you are going to buy has movement speed then you can take Ultimate Hunter.

Grasp of the Undying helps you with your max health and you do more damage on hit when is charged up. So, if you need max health take grasp of undying. Try to stack it but don't get too greedy and you eventually die or have a bad trade.
Aftershock grants you some mr and armor after you cc a champion. That's why I put the Conditioning that it is doing the same in generally but is a very lower %.

Demolish is a rune that destroy turrets. The more max health you have the more damage you will deal. So, this is a rune mainly for tanks.
Take Second Wind to keep your health up during lane phase. You can take Bone Plating to if enemy have burst damage. BUT if enemy is ranged then you take Second Wind without second thought.
Take Overgrowth to maximaze your max health. If they have a lot of cc you can take Unflinching.
with Conditioning do the same work as Aftershock but with less %. Thus,when you activate Aftershock you gain a massive armor and mr.

Take this to take more gold per take down (kills or/and assists). If you find yourself waste a lot of mana you can take and Presence of Mind to increase your max mana and refund some mana after take down.
Legend: Alacrity take it to have some damage. Because you are tank that doesn't mean that you have to take all the runes and all the items defensive. If you want to be an unbeatable tank then you must buy only defensive items.

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This video is excellent to teach you the wave control and all the tips and tricks you must know about it.

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This is a tierlist for all lanes. It's worth watching.