There's a lot of good, basic information in this web page presented in a Q & A format that's easy to navigate to. Of course because it's an overview, the answers to particular questions don't go into much depth, but it gives you a start for further research and the site's worth browsing for more details.

Good lists of questions for family or friends who are trying to hospitalize someone. It's often very important for the person's care to ask such questions -- and to share with the person what they learn.