What do I do next to disassemble my ps3 fat?

[Entryjyt]

I was disassembling this console to clean it, but when I got to the part shown in the video, I didn't know what to do next. I searched online for tutorials, but their ps3 wasn't the same inside as mine. I have a fat ps3, but I'm not sure which model is it. I also shown the model number in the video below. What do I do next? How do I take the motherboard out of the case?
Video: