Help with missing interface board

Hello. Morris from Geckodrive told me to get to this group. Spoke very
highly. Question: Am finishing my "homemade router" but now I'm stuck.
Mechanicals are no problem. Can use steppers or brush servos to drive
with Geckodrivers, easy. Can use Bobcad to draw and generate
toolpaths,easy. Problem, were do I get the "missing board" to take
the g-code and split it out to the drivers.Any comments on stepper vs
brush servos? 600 oz seems to be what I need to move the system.
Thanks Andy