Please advise me on this circuit - Arduino ignition

Hi, I have been trying to get an Arduino to fire a spark plug so that I can then move onto writing the code for my ignition system.  I have actually been on this for sometime and because of my lack of electronics knowledge I feel I am up against a brick wall and I would really appreciate some kind advice.

I have read this article and I am trying to reproduce what has been done here.

[original story: Circuit Digest]

Circuit Digest 09 Jan 16:24