That's got to be the most difficult to answer question ever here.<p>It's like asking how to climb Mount Everest. The flippant answer of course is 'by taking the first step'.<p>What you learn first is different for everybody, just like that first step on to the path that leads to the summit of Mount Everest is different for everybody. It depends, in the first place, on where <i>you</i> currently are.<p>So without knowing where you currently are it is next to impossible to answer the question in a way that would make sense to you.<p>Could you maybe describe a bit of what you already know, your skills and your experience to date? That would help enormously.