It's just a powered usb hub in an RPi-shaped case.
Hopefully you bought a good quality power adapter as well.
The PiHub needs to have power: Plug the power feed from the power adapter into the PiHub - but leave the power off for now.
The RPi needs to have power: Plug the earmarked RPi power outlet from the PiHub into the microusb power input on the RPi.
The RPi needs to be able to share its usb connection with other devices on the hub: Plug one of the usb connectors on the RPi into the usb-input connector on the PiHub.
The other accessories need to be able to communicate with the RPi: Plug your other accessories into the remaining usb connectors on the PiHub.
Turn on power to the PiHub power adapter.
In pictures - see here - http://youtu.be/gysq2KWwqAU
How To Ask Questions The Smart Way: http://www.catb.org/~esr/faqs/smart-questions.html
How to Report Bugs Effectively: http://www.chiark.greenend.org.uk/~sgtatham/bugs.html