seats

Hello everyone, I am new to this and I would like to make a consultation: my vehicle seats (front) are in a pottery too far to be normal.
From there, there is no problem with the positions to the "lying" but the seats are not "stuck" in 90 degrees as it should be. Does anyone know if you can regulate the initial position later? Have you told me that they carry a nut to the side but I can't find it? I would thank you for any help with this topic, thank you very much