OK, thanks.
We will use the given bluetooth module.
My next question is about how to connect the motor driver properly to the the DC motor.
We have two 12V batteries which we will connect in serial to supply the motor with 24 volts. We will connect the arduino, as you noted, parallel with one of the batteries to supply it with 12 volts.
The problem is however, If I connect my motor driver together with my battery to the engine it will obviously not run entirely through the motor driver. In example situations I found on the internet it does.
How will this effect the working of my scheme? If I didn't explain it clearly I can draw it if you want.
PS. We will use this motor driver:
http://www.aliexpress.com/store/product/Free-shipping-New-0-24V-Dual-30A-H-Bridge-DC-Motor-Driver-Peak-60A-for-Robot/710410_634914339.html