If you need the 3rd layer to happen after the 2nd, you can tell that to the spirits and they’ll follow your instructions.
What I would personally recommend, though, is that you not worry about it too much and trust that the spirits will work in the most effective way. The spirits tend to see more than we do. If you tell them the ultimate end result you want they will work with that in mind.
Really if you aren’t too sure about this I’d recommend doing something like the Master Curse from Magickal Attack that’s already formulated and proven to work well. You can certainly do a custom curse if you want though. If you do I would recommend remaining open to guidance from the spirits as to what rituals to do and when.
This makes it sound more complicated than it really is. Just relax. If you ask the spirits for assistance they will respond.