1. Drive Backwards at the start through the doorway.
2.When Driving Backwards up The First Slope in the track you will see a arrow pointing backwards/left then when you hit the White Barrel you will see in a background window and yellow pipes will show up wich is in the shape as a Y so hold Backwards/Left and Press Y, then control your guy to the big box.
3.When you at the gap were pipe blowing steam upwards, you need to hit slope then bail out and if you make it on top of building across gap you will get suck in to the vent.
4.Once you make it over Barrels on top of Slope you will get a checkpoint then drive backwards down slope you will hit a staircase wich will flip so control it land it and then you keep going backwards fall in a hole in the floor then you can drive forward under the floor into a room.
5.The Checkpoint at #4 drive slowly up the slop in front of you, then you will fall, land it keep going forward you will see greyish planks on floor drive on them slowly once entire bike is on it, the planks will breaks or go hidden you will fall to floor below then you will see arrow on wall so drive backwards till your back tire hits a staircase.
6.Near the end you will see a Barrel on ground and two Black pipes/poles sticking up not far from it and you need to gun it forward jump off barrel and you back tire should hit Black pipes/poles while this is happening hold forward and gas, then you should be doing a Front flip you should clear the gap if you do, then drive forward to the edge of rooftop.
or you can just watch the video if you don't want to play the track.
Enjoy!