How do I lay the middle passanger seats down in a 2003 GMC Yukon?

My dad gave me his older GMC Yukon and bought the EXACT same truck in a differerent color..... dont ask.... It is a 2003 Chevy Yukon. The truck came with three rows of seats. The driver side, the middle seats, and the back row seats. He took the back row seats out. Now I have only the front seats and the middle seats. The question is, how do I let down the middle seats so they can lay flat? I need the truck to have more space so I can put some stuff back there becasue I am in the process of moving. My brother and I tried to let them down today, but we couldn't. It has to be a way to let them down because there is carpet on the back of the seats that matches the back of the truck. If I cant find a way to lay the seats down, I will have to get a UHaul to move my stuff. I would RATHER put everything in the truck and save money rather than getting a UHaul. I only have a 55 inch tv and clothes; so I REALLY dont need to go the UHaul route.