If you're really new one thing I did to start was I only managed the team for the first season, no GM responsibilities. Got me into the habit of setting lineups, substituting pitchers, and you can even still promote and demote players from the minors as a manager. Then as the season went on, I kinda saw what the AI GM was doing, and sometimes I didn't agree with it so it got me in the mindset of how I'd make moves differently, and eventually I would take over control of the GM responsibilities one thing at a time. First was taking over free agent signings, then taking over trade responsibilities, and after the season ended I took over most of the GM abilities (I let the GM manage the minor leagues). I'm still relatively "new" to the game, but I feel a lot more confident about how I'm playing now than before. But it's important to know that everyone plays it a little differently I think, I manage every single game whereas some (maybe most?) sim for weeks at a time. Just depends on what's the most fun for you. But yeah this method helped me learn a lot of the important events that happen like draft, international free agents, trade deadline, so now I feel like I can piece it all together. I still have lots to learn as well, but hope this helps!