The TPA3118 module comes exactly like you see it in the pic, all components are already installed. Yes, you can get the exact same thing from Amazon, eBay, etc. It's offered here as a convenience. (Just be sure the pinout and dimensions are the same if you plan to use it on one of the upcoming projects)
This isn't intended to be used as-is, it will be treated like a large IC and be soldered to a larger interface board.
You could of course wire it up yourself, but it doesn't have any sort of volume control or preamp. The upcoming interface board will take care of that.