You don't need to charge it before you use it for the first time, it should already be at least pertially charged. All that this page says is :
For proper reporting of the battery’s state of charge, be sure to go through at least one charge cycle per month (charging the battery to 100% and then completely running it down).
Charging the iPad : http://support.apple.com/kb/HT4060
The iPad mini came with an USB power adapter and a lightning cable.
Plug the lightning cable to the port on the edge under the Home button (the large button on the display).
Plug the other end into the USB adapter and plug the USB adapter to the wall power socket and switch the power on.
Download the user manual will get you up to speed: