GRBL with AdaFruit Stepper Motor Sheild?

Hello I have been having endless problems trying to get my CNC ready Milling Machine to work,,, The machine itself is a Proxxon MF70 CNC Ready Milling Machine which comes with 3 NanoTec SC4118L1804-KPRO Nema 17 Stepper Motors. I have Purchased myself an Arduino Uno R3 and an Adafruit Stepper Motor Shield: Adafruit Motor/Stepper/Servo Shield for Arduino v2 Kit [v2.3] ID: 1438 - $19.95 : Adafruit Industries, Unique & fun DIY electronics and kits

However I am a Complete Novice to Installing and Setting Up such machines. This means I have no understanding of how Arduino's, Stepper Motors or any shields boards etc work together. I wish to use Generic G-Code on the machine and need a dummies walk through on the best way to approach the project.

I have approached Proxxon asking if they supply a Control Unit but they have stated they do not supply them separately and therefore i am looking for alternate methods, I would like to keep the project as cheap as possible as i am on an apprenticeship wage (not much) and so far have spent around £200 on stepper motor drivers and other items at the advice of other Arduino related project sites including adafruit themselves. I am greatly appreciative if there is someone out there who can help me as i said earlier i haven't a clue where to start with regard to hardware let alone software.

 

would this be everything i need or would I need anything else?