Concealing your mechanics is Floristry 101. I inserted a tall piece of Italian Ruscus right next to the tallest extension rod to help conceal the rod. I also place another small ball of floral clay to the side of the second extension rod.
I inserted a second blade of grass and wound it down and around the lower votive candle rod.
This is where the fun of designing comes in as you see it grow and take shape.
I start adding other staggered heights of mixed greens in the center. Again, my aim is to make the rods blend completely into the design, so that your guests see the flowers, candles and greens . . . not the mechanics like the rods or the florist cage.
Stagger the heights of the greens just like you did the rods. Do not overpower the candles themselves - they are meant to be a focal point of the arrangement.
Here's a closeup of the greens and grass placement.