During play in editor, you can just keep the curve editor open to this asset and right click to add a new key or move around the existing keys (as you would with any curve asset). The changes should be immediately evident in your scripts that are using the values from the curves.
This is not designed to have new points added at runtime outside of editor nor via function calls. It might be possible but I am not sure. It may require some code changes to make a function to do so at runtime if this is something you want to add.