In your case, you might want to try a Quick-Start league and just select any team and begin playing. Get used to the interface, the options, the routines and requirements, a lot of which you'll develop on your own. Of course, a scan of the online manual couldn't hurt and may provoke further questions that you don't know you have yet.
I wouldn't approach the game, the quickstart that is, like an investment you'll be making for a lifetime, but rather a self-tutorial to familiarize you with the game environment and just how you want to fit into the scheme of things.
Feel free to post a question anytime about anything along the way. We'll help best we can, and rest assured the majority of us were where you are right now. On more than one occasion, we all return to that sense of being overwhelmed, however short-lived, even now. That's the beauty and richness of the game's depth. Start slow. Experience. Plan later. All the best, until then.