FROM WHERE I HAVE TO START

IMHO this technology is way too complex (and subtle) to have a reasonable expectation that you will become professionally competent by following a self tuition approach. If you don't have anyone more experienced who can mentor you, get yourself booked at least on the introductory developer course that Adobe and/or it's partners provide. Trying to go it alone will mostly likely take a very long while and without a good grasp of the fundamentals you are more likely to take a wrong turn or two and get yourself into some bad habits and poor practice. This is an enterprise grade product, it deserves a level of training commitment commensurate with that investment.

my 4 cents

Fraser.

To add an entirely self-serving comment, one of the engagement models we following in Adobe Consulting Services (and the same is true of many of our partners) is a mentoring model where we come in and set up the development process (adapting to whatever you already use, although we obviously have a perspective on what process works best for AEM projects) and tools (ditto) and then work over a period of weeks/months to transition development responsbility over to the customer team. In my experience, this (paired with training) leads to a solid outcome as developers are both being productive (which feels good) and learning (which has long term benefits).

Justin

thanku so much