On the left side of the photo is the Subwoofer Pre-Out connection. This connection allows the low frequency signals from the receiver to be passed to a Powered Subwoofer. In other words, the subwoofer must have its own built-in amplifier.
On the right side of photo are the standard speaker connections for Right and Left Front Speakers. If you are planning to use the AVR147 as a stereo receiver, this is where you would connect your stereo speakers. However, if you are planning to use this receiver for home theater surround sound, you would also connect speakers to the Right and Left Surround and Center speaker terminals. The AVR147 has amplifiers to power each of these speakers.
For some visual tips on how set up speakers for surround sound, check out the next photo, which is excerpted from the actual AVR147 User Manual (used with permission).
Lastly, on the far right side of the photo is a Switched AC Convenience Outlet. This is for providing AC power to another device, such as CD player, DVD player, etc... This outlet is only active when the receiver is on.