No record :-(
Go to Rox and Braham, wait for the mobs to sapwn, kill them. After killing them, proceed into the tunnel, there are 5 caves in the tunnel, each having a group of mob in it, after killing the mobs, pick up the Boulder that spawns and place it on top of the steam burst (a red gear indicates it's place). After killing all 5 group of mobs and placing all 5 Boulders on the red gears you wait for the Drill to make it's way out of the tunnel.
You exit the tunnel and kill the group of mobs coming to you. Then proceed to the Steam Walls. The first Steam Wall is unpassable, each Steam Wall knocks you back and damage you. After the first, you can pass the following Steam Walls by walking backwards in them (do not walk into them with low hp, thats downs or even kills you). Make your way on to the weapon testing arena.
You enter the arena and survive the 3 weapon test, after you survived the second and third test a Molten Protector spawns, kill it before it gives the Thermal Core Invulnerability. The weapon test types are in random order:
You have to dodge, block or reflect the Fire Tornadoes coming towards you, you can use the Thermal Core in the middle to your advantage. The Tornadoes apply Burning. After surviving the test you can damage 25% of the Thermal Core.
There are also multiple safe spots to prevent getting hit at all.
You have to avoid, block or reflect the Fire Barrage falling on you, a Mesmer can use to reflect, the Druid can use (Staff 5) in the middle of the AoE to absorb the projectile. The AoE after the projectile landed applies Burning. After surviving the test you can damage 25% of the Thermal Core.
At 25% and the boss after
You have to damage the core as fast as possible since now all 3 weapon test types are active. After you killed the Thermal Core the Weapons Test Engineer comes down. Kill him to finish the fractal.