Don't worry about any of those fields. They will be created or modified as needed.
The best way to modify the XML is to use something like this macro of mine:
Just use it to edit action or actions you want to modify, delete the old actions, and paste the modified actions in. If you mess up anything, they'll refuse to get pasted back in. You can always use the editor's Undo if you need to. And you can work on a copy of the macro if you prefer.
Personally, I use KMET all the time, although I usually work on the JSON version rather than the XML because it's easier to understand the structure.