Track Process
Below is an example of a track being made (Hyperdrome Arena)
Laying out the layout after finding the right materials
I've also used Blender to make layouts but that's more of a recent development
Placing down basic structure
Decorating and placing hazards
Afterwards, all that's missing is track setup, right now track setup uses proprietary tools that are not yet open to the public. I hope this is enough information for now!