Step 1: buy a Stygia Dowser from Ve'nari. Green glowy Stygia Nexuses will show up on your map.
Step 2: gather enough Stygia Dust and Silver to make 20x Stygia Bar.
Step 3: buy a Partial Rune Codex from Ve'nari.
Step 4: go find 3 Rune Pages which will now show up on your map.
Step 5: loot the Soulforger's Tools from Soulforger Rhovus
Step 6: assemble the Armored Husk at the Soulsteel Anvil on top of Domination Keep
Step 7: find a Stray Soul in the River of Souls
Step 8: bind the soul to the armored husk at the Binding Altar
Step 9: ride the feral shadehound and use the runes in your actionbar in the order your codex says