Next, ignore the beams, and focus only on the water track. Despite looking like it's climbing up, it's actually totally flat (i.e. you could make it from one sheet of wood). But tilted slightly so water flows from the start to the end.
Additionally the entire structure is not actually sitting on the garage floor, but rather is high up in the air, and the camera angle obscures this.
Hidden under the structure is a pump and an outlet at the true start of the track.
He pours water into the catch basin at the end of the track, and that same moment someone else starts the pump. If you watch closely you can see how it looks like the water he pours is being "swallowed", and does not actually flow down the track.
The water from the pump flows down the track, and out the spigot over the wheel and into the bucket.
Next you place beams carefully cut at angles to make them look like they are holding the track - but actually they are open on top.
But this is a pretty amazing piece of work.