Collections are a mechanism for organizing your books on the Kindle. They are like tags. You can create a "Mystery" collection, for instance, and add all your mysteries to that Collection. There are sorting options for Collections, too. You can add a book to more than one Collection.
If the wireless is turned off, of course it does not look for anything via wireless. You only need wireless to download new books, search the web, etc., not to read. The wireless is strictly controlled by the user. If you buy some new books, for example, you can turn on wireless, click on "Sync and Check for New Items", let them download (takes only a minute), then turn the wireless back off. Or, of course, you can transfer books to the Kindle via USB.
No special drivers needed. The Kindle just looks like a thumb drive when connected to the computer. Books go in the "documents" folder of the Kindle drive. Background music goes in "music", and audio books go into "Audible".
It has 4GB internal storage, with approximately 3GB available to the user. That will hold a lot of books. No real need for a card slot, unless you want to store many thousands of books on the Kindle. I only keep a hundred or so on mine, at any given time. Plenty to read. Some people that use a lot of audio books can run out of room, but I'm assuming you are more interested in ebooks.
You can download the User's Manual from the Kindle Support Documentation page:
http://www.amazon.com/gp/help/custom...deId=200317150 (pdf format, for reading on the computer). It comes pre-installed on the Kindle, too.