There is a WIP PR for documentation on this that has everything that is on this tutorial, and will soon have more such as Items and Entities. Here is a link to the PR.
In this tutorial I will be explaining how to use the Animation State Machine or Forge's Animation System on a TileEntity, though this can be applied to Items or Entities as well.
Let's start off easy, with the code for the Block, TileEntity and the binding of the TESR.
This is where the confusion comes from for the animation system. The armature and ASM JSON files. The ASM file has it's own "grammar" which is outlined by fry, here. This is a little vague so I will try to explain this a bit more, so that it is easier to understand with what I have come to know through my own attempts at using this system.
Sample BlockState File
I'm sure there are typos or possibly something I have missed or not explained well enough, so I would love some feedback even on formatting issues. I will also post my raw notes on this stuff that might contain extra information.