Do a search or check under "Junkyard Dogs" for triangle braces.
It's not hard to do and if you really want to see how they go together, go to the junkyard and look underneath 80's Cutlass' and you will see them and how they go in. Do yourself a favor and grab them while you are there as they are the same as the aftermarket ones you can buy, and you'll save some money.
Good luck!