I agree with what Brad K said, and as for where, click on your league's Name, then League Settings, and then Financials is where a lot of that stuff is, but, like Brad, I'd also recommend going through each of those settings screens and determining what you want each set to.
I'd even recommend going so far as creating an electronic file noting what settings you changed, what you changed them to, and maybe even why you changed them. That way when you create a new league you can easily recall what you did and why, instead of going through all those decisions again later.
You'll probably need to reference the manual a lot as it likely won't be apparent what a lot of the settings do and while OOTP25's manual isn't up yet, just use
OOTP24's (the manuals don't usually change a whole lot between versions).
Going through that process can be a bit of a slog, but it should help you create the best league you possibly can for your own preferences. You'll also probably learn a lot about the game you might not otherwise. I've certainly learnt a lot about it by doing that.