Hello - for the marble top the rubber stoppers are not to be used but rather the screws are to be used to attach the top to the base. Below is a brief assembly description,

* Place the top upside down on a flat soft surface (carpeted floor or place a blanket or towel on the floor) this exposes the wood core used to screw into (grey painted area on the underside of the top)

* Now take the base and align the outside edges to match the upside down top, this will place the screw tabs on the base within the wood core area.

* At this point, proceed to screw the provided screws through the tab holes and directly into the wooden core (please note that the top itself does not have pilot holes)

* After all screws are attached you can flip your now assembled table right-side up.

Take Care.