This quest offered by [npc=252312] gives you [item=265822] to use if you haven't unlocked Mechagon, though it's still faster to use it either way.
You will need 10 [item=166846] to buy the required item from [npc=150716], they drop from mobs around Mechagon.
-- What follows is not required for completing this quest. It's a simple guide for new players to unlock Mechagon as it's likely Blizzard is doing those decor breadcrumb quests for discovery --
Alliance
1.a) Start A Dying World by talking to [npc=154464] in Boralus. Just take the portal to the zone, no need to complete Bfa introduction.
1.b) If this quest isn't here, visit Silithus and directly and talk to Magni Bronzebeard. It needs to be Silithus BfA so talk to [npc=128607] to phase yourself properly if you don't see Magni.
2) Do the questline until you get [item=158075].
3) Do Send the Fleet in Boralus sending you to Nazjatar. Do the introduction quests until you unlock world quests.
Doing Uniting Kul Tiras may be required for this step, which is getting three reputations to friendly (see quest).
4) Do The Legend of Mechagon in Boralus.
5) You should have unlocked Mechagon and can access it for good without this quest's item.
Horde
1.a) Start A Dying World by talking to [npc=154465] in Dazar'alor. Just take the portal to the zone, no need to complete Bfa introduction.
1.b) If this quest isn't here, visit Silithus and directly and talk to Magni Bronzebeard. It needs to be Silithus BfA so talk to [npc=128607] to phase yourself properly if you don't see Magni.
2) Do the questline until you get [item=158075].
3) Do Send the Fleet in Zul'Dazar sending you to Nazjatar. Do the introduction quests until you unlock world quests.
Doing Uniting Zandalar may be required for this step, which is getting three reputations to friendly (see quest).
4) Do The Legend of Mechagon in Zul'Dazar.
5) You should have unlocked Mechagon and can access it for good without this quest's item.