Safari Books Online is a digital library providing on-demand subscription access to thousands of learning resources.
Videos need to be watched in landscape mode. Touching the center of the screen opens up the option of play/pause. The bar next to it is for jumping to a particular scene. The volume control is at the top of the screen so that you don’t have to go to the Quick Settings menu to adjust it.
One of the most helpful buttons is the Back Ten Seconds button in the upper-left corner. It is good for situations where you might have missed something; you get a quick rewind.
If you are concerned about whether you need to be online (synced with a valid Wi-Fi hot spot) to watch a video, it is certainly something to consider. Like the Newsstand, Books, and Music on the Kindle Fire, Videos has a Cloud or Device option (located at the top center of the screen).