Going down the baseball rabbit hole, eh? That's awesome. I did this a few years back with soccer. Went in totally blind and now I'm a bona-fide addict. I also spend an ungodly amount of time playing Football Manager which has actually eaten into my Show playing time.
I think a good place to start would be here:
https://www.pbs.org/kenburns/baseball/baseball-for-beginners
As for tutorials, I would find them to be lacking for someone coming in fresh to not only the Show but the actual sport. BUT...if you go to settings -> Gameplay -> General -> Tutorial Tips = On. Then you should get sporadic popups at least explaining the mechanics.
I would then set the difficulty to Beginner. Then on the main menu, scroll down to "Exhibition" and just play classic mode for a few games. This should give you many of the tutorials as you play.
Full disclosure, I've been playing this game for years so I haven't used the tutorials in some time, so I really don't know how helpful they are. But figured it's a good place to start.
Lastly, highly recommend just watching real-life games when you have time. There is A LOT to baseball and it'll take time. But you should find it rewarding because it's a great sport.
And pop into this post if you have questions. I'm on here a few times a day so happy to help out where I can.