Captain Edward J. Smith, the master of the Titanic died in the sinking. As to getting started, you can parse the different threads to get a sense of what interests you. I'd also suggest getting books on the subject. There are several of us here which can point you in the direction of some useful material.
Primary sources are a must of course, and one place you can start off list is the Titanic Inquiry Project at http://www.titanicin quiry.org/ which has the complete transcripts and reports on the U.S. Senate and British Wreck Commission's investigations into the disaster.
It might help also if you could spell out what interests you. Passengers? Tech issues? Californian Incident? There are members here who specialize in these areas who can help out by pointing you to the most useful resources.
Welcome Charley. My suggestion, if it is passengers you crave, is to go back to the main entry page, and you will see an area with a list of passengers and crew seperated by class and job classification. Click onto that and start looking up whoever you would like to learn about. Just a warning... it will take weeks and weeks, but should be completely enjoyable. If you want to see if there is any more on a person, many of them have been discussed on the message board. A keyword search will bring them up. Anyhow, good luck and welcome to Encyclopedia Titanica!
Both Mike Standart and Collen have given excellent ideas.
You have mentioned the captain and the sister ships. My suggestions would also include reading through the Crew thread and perhaps the technical thread for a gleening of information that relates Titanic to its sister ships and typical crew issues.
There are threads for other ships and the sister ships may come under them as well as some others such as the lusitiana.
Welcome. And write something about you and what you are interested in the introduction thread.