It's different for each sheet, so it's kind of hard to say. Also, some animations are designed for flexibility-- for example, multiple animations in a row could be used together for a longer effect, or used individually.
I might write up some sort of guide eventually. Good idea!
It is kind of hard to just drop and use these into a MV project. How do I set them up in the editor? I added a sheet and told it to do 15 frames (the fire one)for example, and no animation shows up when I click Play in the Animation area. Do I have to do something different to get it to work? There was no .json file either.
You need to create the animations in the editor using the frames from the animation sheet. There is an example in the discord channel in response to your question earlier today.