First quest might only pop up after killing Argus once on that account. Relog should help, if it does not show up for you or close your client completely, if you have done step 9 and The Speaker's Call does not trigger (as described here).
You can switch the zone phasing at Zidormi, if you can't see your quest giver in Silithus.
If you just want to empower your artifacts quickly, you can skip the optional quests.
- [quest=49977] - speak with Nathanos in Orgrimmar
- [quest=50341] - click his dialogue (Video)
- [quest=49982] - travel to Silithus. You can use the portal to Uldum in Orgrimmar
- Lazy Prospectors! - click 10 goblins
(optional) No Spies Allowed - kill 10 stealthed agents
- (optional) Desert Research - speak to [npc=132040] near you
- The Twilight Survivor - kill [npc=132203] and (optional) accept/complete A Wee Bit O' Cloth at the toilet
(optional) The Source of Power - collect 10 brains
(optional) Larvae By The Dozen - click 12 broodlings
- Khadgar's Request - speak to [npc=130033]
- The Speaker's Perspective - go to Magni Bronzebeard in Silithus
- The Blood of Azeroth - return to Southwind Village
- [quest=50300] - speak to [npc=132140], he'll transport you to Magni
- [quest=50057] - click the dialogue (Video)
Questline (incl. optional quests) took around half an hour, started from Og/Uldum. Without optionals and cinematics it were 10 min.
Now all of your character's artifact weapons are empowered to maximum.