Sorry for the slow response -- we did get a 30th person, but openings do come up every so often.
Basically you manage a roster using 3rd party programs that were developed way back when the game was released. The website is the real charm because you can see everything about all players (edits, statistics, etc.) throughout the 120-year history of the league. This includes awards, All-Star teams, Hall of Fame, statistical records, etc.
Anyhow, you manage your roster, including all three levels of minor leagues and a financial system that is integrated in the website. You can trade players, draft picks, and money with other owners.
There are three sims a week (M W F) that are 10 games each. This equals a month in-season. So 6 weeks real time = 1 season. Then there are two weeks for playoffs/World Series and offseason Free Agency and rookie draft.
If you're at all interested, let me know! You could always watch the season from afar. I could get you an account to log in and chat or talk with anyone in the league if you'd like.
It looks more intimidating than it is if you log in and look around. With someone helping you out, it's not nearly as complex as you'd think. Don't get me wrong, you can spend a lot of time tinkering, looking for trades, etc., but you don't need to. It's one of those things that you are best off learning as you go before doing too much.
Check out the website if you haven't: mlbcsimleague.com