The entrance toMolten Core
First of all, you fly to Burning steppes, then mount to Blackrock mountain and reach the ring of fire.
There is a chain that holds the mockery in the middle… Cut on that chain and move down to a place where a blood elf masters and a low quest gives… Take q and enter blackrock depth. Use the levers.
Open the doors (without the key for this dungeon, it is endless.) If you have the key, you can sweep the BRD and reach the end. At the end of this dungeon is a portal that is the way to enter the MC. Next to the portal, there is an item quest from the belf that you should get, then if you are a raid, you can become a mc.
If you die in mc, go to the same belf with ghost and he will send you to MC to live.
This is the way for those who want to find mc for the first time. When you deliver q, you can enter MC next time without entering BRD.