Quote: "how exactly do they make money off browsers btw?"
Hodgey's right about the web browser. You won't make money off it by selling it. In windows alone, you'll have to deal with IE (yes many ppl use it still), Firefox, Chrome and Opera. All of the are free. Your best bet is to give it away for free and have it
add-supported, then offer an add-free version for a minimal price like 10 USD. Also, if itto be a success then you've got to make it look good and feel comfortable as well as run a decent campaign to advertise it.
As for making as OS, that is not an easy undertaking. It would be easier to take something that already exists, like Linux, and build on that. Linux is fully open-source and there's a massive community that you could recruit from and collaborate with (which is why there are so many Linux flavours). Google it, you'll find 100s of forums and sites.... However, your project would have to be open-source - it's something the Linux community feel strongly about.
Finally, tutorials. Can't help you there. Wouldn't know where to start looking but if you are writing a web browser, I suggest you study up on "how it all works" and go from there. I doubt you'll easily find a step-by-step guide.