I am interested in collecting Omegas, but do not know where to begin (I am not new to watches, just Omegas). Is there a good guide to help the beginner understand the company's various models and their variations? Or, at least the first released examples of specific models?

I tend to collect "1st"s. For example, I would want a first-year Seamaster, which I understand is 1948. Were there multiple movements/dial/case options available for the Seamaster in 1948? If so, is there a guide that covers these kinds of variations? And for other significant Omega models?

Thanks!