Not sure if you have leveled an Orc yet, but if PVE Tanking is the top goal, I would consider rolling an Imperial or Dunmer.

The Swift Warrior passive will not do much could in PVE, and you might be better suited with the larger raw stat increases of Imperial. Dunmer is also a good choice because as a tank the Magicka will help you as well. Any race will work though.

Many people have different takes on DK tanking. Also there are a lot of changes coming in DB that affect tanking (changes to block cost reduction/sturdy trait, constitution heavy armor passive buff etc), so it is hard to say what the optimal set up will be after the patch. You can find some builds that are built for ultra high mitigation, others for fast ultimate generation, some run hybrid tanks that also do damage.

You need to have a way to maintain your stamina so that you can continue to block. If you run out of stamina in certain fights and cannot maintain your block you will die. DK's regain stamina when using Ultimates, and also regain 5% stamina when using Earthen Heart abilities like Igneous Shield and Cinder Storm. For these reasons they make great tanks since you can overcome that lack of Stamina Regen while blocking with these methods.

My imperial stam DK shoots for a large stamina pool, with high mitigation, low block cost, and high magicka recovery. Its good for crowd control, resource management, and survival. It does not do much damage, but buffs the groups dps with aggressive warhorn. I run sword and shield on both bars. I run 5 pc Armor Master (4 body, 1 shield) and 4 pc Kagrenacs on my front bar. Then 4 pc Armor master, 5 pc Kagrenacs on my back bar. 3 pc Transmutation Jewelry. I am at about 25k health, 30k stamina, and I think 15k Magicka and 2000 mag regen. All attributes in Stamina, all gear enchants stamina, tristat food. Atronach Mundus stone for mag regen.

Bar 1: Unstoppable (provides Major Ward and procs armor master, my mitigation goes up 10,500 when using this ability)
Absorb Magic (Reduce Block cost, and increase block mitigation)
Heroic Slash (Builds Ultimate and reduces boss damage)
Igneous Shield (Provides a weak shield, but also gives 30% increased heals and returns 5% stamina)
Pierce Armor (Taunts enemies and reduces their armor)
Ult: Aggressive Warhorn (A must have skill, buffs the groups damage by ALOT, and gives a flood of resources due to
Mountain's Blessing passive)

Bar 2: Coagulating Blood (Decent Heal when low, magicka based which is good since it doesnt drain stamina, provides
increased healing)
Cinder Storm: Snares enemies and draws aggro. I chains mobs in and use talons so DPS can use AOE's
Choking Talons: Roots enemies and reduces their damage. With high mag recovery I can lock down mobs indefinitely
Fiery Grip: Pulls mobs to you so you can talons or Cinder Storm. Good way to group up archers/casters to dps can aoe
Inner Fire: Ranged Taunt that uses magicka. Good to use when mobs are at a distance or stam is low
Magma Shell: Basically makes you immortal for 9 seconds. Good for times when the team wipes or you are under alot
of pressure.

Basically I stay on Bar 1 for boss fights. Keep mitigation high with Unstopppable. Rotate Pierce to keep aggro, Heroic slash every 9 seconds to build ulti, Light Attack every 9 seconds to build ulti, Igneous Shield every 6 seconds to build ulti and regen stamina. Use Warhorn when low on resources, but save it for boss phases if you can.

Bar 2 to gather trash mobs. drop cinder storm on a group, talons them in. Use chains to pull stragglers in and keep talons up.

If my team wipes I will buff Unstoppable and Igneous Shield, then bar swap and rez players quickly with 5 piece kagrenacs.

Many people can give you there setups as well, and you can find good build videos on youtube. This has worked for me. I have used it in all 4 man content but have not tested it in trials.

https://forums.elderscrollsonline.com/en/discussion/254916/ultimate-tank-build/p1

Up-front disclaimer: This is for an ultimate regen build and is widely utilized (in some form or another) for end-game trials tanking.

if you run armor master need to run engine guardian. for end game trial tanking the long fights will be hard with resource management proccing armor master all the time.

with heavy reinforced armor and footman or pariah you should not need to run armor master

5 piece several options tava - ulti build, hist bark
4 pc armor master, alessias bulwark or song of lamae