Sure, you can dig around in the ebook pre-loaded to figure it out, but here's a collection of things I wanted to know right away and had to figure out.
Step 1: Change the volume
That's great, but no volume buttons? Nope, it's stuck in the settings menu. To get to those, tap the little gear on top. Now you can change the volume by selecting "Volume" and sliding the volume control.
Step 2: Locking the screen
OK, fine, that makes sense. Still annoyed with the lack of volume controls.
Other controls in there do what you'd expect as well.
Step 3: More settings!
Step 4: How to put ebooks on your Kindle Fire
Here's a total list of files you can transfer over: DOC, DOCX, PDF, HTML, TXT, RTF, JPEG, GIF, PNG, BMP, PRC, and MOBI. One format that is NOT here is EPUB so you will need to convert these to MOBI with a program like Calibre before transferring.
To do this you will need a micro USB cable and it didn't come with the Fire. If you have a previous Kindle, the same cable will work. Otherwise you can get one online for just a few bucks.
to transfer the files over, just plug the Kindle Fire in to your computer and transfer files into the appropriate Kindle folder. So put books in Books, and pictures in Pictures.
Alternately, you can email the files to the email address on the screen. It should look email@example.com. Your email address that is your Amazon.com account will automatically be able to do this. You will need to authorize other email addresses, however.
Step 5: How to take screenshots
So unless you really, really want screenshots, don't bother.