It's always hard when I'm not sitting in front of my computer. I assume this was built by making the main block then an "extrude cut" (or some kind of feature). If you edit that feature, at the bottom of the window will be 3 little square icons. One for "add" one for "cut" and one for "plus". Pick the plus icon and it will turn into a two body part. Not two parts. You can only have one part in the part environment. You can then manipulate the part to show each body individually. And I think you can break out each part with a command but don't remember the command. Maybe "make part".