Your not alone. I forget things that I don't do often.
In WTP build your vessel. Remember default is a flat ring. Shown in the upper left of the screen. It is a drop down menu.
-Select the ring you want to be a "stave
- I suggest changing to cutaway view.
- change by using the drop down menu from flat to stave
- Note, the input changes, So you can input stave height, etc.
- Once done, the cut summary view will give you the miter angle and blade tilt to make the staves.
I'll point you to a thread where there was some good discussion about Staves and Compounds which gives a method for creating Compound rings (typically short rings) which will have a flat bottom and top after cutting the segments. This will work if the ring is going to be short and the segments are made by cross-cutting boards. It will not work if you are going to make tall Stave rings where you cut the angles into long boards while ripping - similar to what you would do for making a stave drum.
Here's the link: Title: Stave vs compound