lol.. you dont understand all the tactics, you probably dont know 1%. there are world champions that dont understand half of whats going on in there. you learn as long as you are in this sport, its so complex.
i remember hopkins saying (i think after pavlik) hes still learning new things about boxing every day. the idea that some mma fan who doesnt even know the sports history understands all the tactics inside the ropes is laughable.
as for your question there really isnt a crash course to boxing, pick an atg and go through his career. along the way you will probably see him fight other fighters you like just as much or more, check them out too. then move on, either to a diffrent era or division.
it will take years to cover the sports history and even longer to understand everything thats going on at the highest level, but if you are a true boxing fan you will enjoy finding out.