I leave my tower on the floor next to the desk and all of the cables are long enough to reach even when it's at standing height. There is a tray below the back

I leave my tower on the floor next to the desk and all of the cables are long enough to reach even when it's at standing height. There is a tray below the back edge of the desk that you can rest smaller objects on, like a USB hub. I believe they also make a bracket that attaches to the underside of the desk that can hold your tower, if you need.