Arduino Handyboard combo


I want to use an Arduino with a HandyBoard for an autonomous GPS guided vehicle. But for various reasons, I am using the arduino for interfacing the guidance system. Currently I have modified some guidance code to send high/low output to five seperate pins. I want to be able to hook those up to five pins of the Handy Board and read high.low inputs. Then have the HandyBoard control the four motors.

I have it as high is backwards, low is forwards, and all set to low plus fifth pin set low is stop.

The Handy Board's pin layout is gnd, +5, input. I was thinking to have the four Handy Board gnd pins connected to the arduino's ground, then connect each individual Arduino pin to one of the four Handy Board pins, and then finally connect the input pin to the ground pin on the Handy Board with a resistor. This is because from looking at schematics, the ground/+5 are not connected to the input.

I tried to attach schematics, but I don't think they can be seen.

Sorry for my recent amount of posts, I am somewhat new to electronics.