Jan, the screws are under the diamonds. These are made of rubber and you can carefully pry them out with a pointed thorn or a small screwdriver. Often, however, they are already in a very bad condition because they have already been taken out several times because of the change of the cloth. Unfortunately, very few pay attention and damage them most of the time. Not infrequently they are completely missing. After removing the screws, it is possible to lift down the entire frame. At the corners, the wood is connected with metal wedges. That can break if you don’t pay attention. The wedges can be knocked out with a blunt thorn if you want to completely disassemble the frame.
