@3D_Laser here are some pics for ya.
First remove the black plate, then two nuts hiding under that. And the other two are on opposite side. If course you will need to remove the stock bed as well.
All the K40 are not build the same. at least 2 types of bed table. (that one based on extruded profile (like Chirag), or bend metal frame (like mine, see my mod), the belt tensioner could be locate on front or back of the machine, the motor are not at the same place too.
like here the bed table is screwed on the profile and easy replaced by honeycomb. the other one, more stiff, it’s more difficult to change as you need to cut into. But my bed table is hold by 4 screws underneath, the air exhaust by 4 screws at the back, simple.
I think I’m going to do this I have to take mine apart to square it all up anyway. I’m not looking forward to rebuilding this thing