All the information you find on the Internet about this. Including the Google AI’s response is BS!

There is no little hole where you have to poke a paperclip I to or any of that nonsense.

Behind each upright is a small metal tab that you need to press to release the upright. Release one side hold it up with a little pressure and then release the other side. See my photos.

I had to cut an old seat open to see how it works.