This is quite a fixture for your Dewalt router.  I use mine on the DW-621,  so I use the thinner set of rods and extra set screw knobs that come with  it.  It has a thicker set of rods for the 3hp routers.  You rough-adjust it  by sliding it on the two rods that fix to the base of your router and  locking the set screw knobs.  You can then "fine tune" it with  the center knob and lock the set screw knob on it.  The large picture above  will make these explanations clear to you.