I have mind sitting in the bottom compartment in the front of my 800D where there is a cage for drives extention. Its not even connected to anything its just sitting on the floor. It really does not matter where you put it.
It will fit into the hot swap bays, but I have two HDD's in there already and the other two connections are broken on mine. Plus if you have a Sata3 SSD and an old 800D without the Sata3 upgrade on the hotswap you will bottleneck the drive if you install it into the hot swap drives.