Q:

Where can I find a thorough introduction to Android?

I recently bought an Android product (HOTT MD500), with no English-language manual. I've used Linux for more than 10 years, so I generally have no difficulty adapting to various interface changes, but the conventions used on the Android interface are a bit alien to me:

How to close programs.
How to switch between open programs. Are they even open still?
How to properly shut the device down.
When to use the SD card, when to use the internal flash drive for storage.
What tasks it is capable of doing.
What version it is. How to upgrade. Or should I?
What its limitations are..
What not to do so that I don't break it.

Is there a good manual which provides an introduction to all of this?

A:

Google do actually publish Android manuals for each major version, unfortunately they do hide them fairly well.
Your phone's manufacturer and/or your network/carrier may also publish manuals for your phone that will include the major changes they've made from the base Android (for example a lot of manufacturers customize or replace a lot of the Android UI with their own version, such as HTC's Sense, or Samsung's TouchWiz interface, they may also modify/replace default apps to work better with their hardware or interface, the Camera app is often one of these). In your case it sounds like the manufacturer unfortunately probably doesn't have an English language manual, on the plus side they probably haven't done much customization to the base Android experience.
Google's Android manuals:

Android 2.2 (aka Froyo)
Android 2.3 (aka Gingerbread)
Android 3 (aka Honeycomb) tablets only, not available for phones
Android 4.0 (aka Ice Cream Sandwich) actually a Galaxy Nexus manual, but as that device is pretty much pure ICS, it should be OK

A:

I don't know about a manual (I never found one) but ...

How to close programs.

You don't. I mean, if you want to stop running applications, that's under Settings > Applications but otherwise, you mostly don't.

How to switch between open programs. Are they even open still?

If you long press the "home" key you can move between the last few applications you had open. 

How to properly shut the device down.

When you hold the power key for a few seconds, you should get a few different options, depending on your OS version. Powering off is definitely one of those options. That's the best way to shut it down.

What version it is. How to upgrade. Or should I?

Find the OS version under Settings > About phone (should show a Kernel version and a Build number. I'm pretty sure you can't upgrade without rooting it, but there are some good insights on rooting your phone right here (and no one definitive answer, for better or for worse.) How do I root my Android device?

When to use the SD card, when to use the internal flash drive for storage.

That's a good question, one worth asking / looking for answers to here.

What tasks it is capable of doing.

Google does have some good general material on this one.  

What its limitations are..

There's no good answer to that one, unfortunately. 

What not to do so that I don't break it.

Don't throw it from high buildings ...

A:

Complete Android Guide is a pretty good introduction/starting point for free on the website, available as an ebook or an app on the market.
http://completeandroidguide.com/

