Simply connect the battery to a computer or AC power via the USB / microUSB cord provided so that it can recharge. Four LEDs are present on the top of the battery to indicate the charge level. An LED = 25% load. The four LEDs in total represents 100% of the load. It takes about eight hours for the battery to recharge. It's a bit longer if it is plugged into a laptop it will then take about 15 hours.
There are two USB ports on the underside of the battery, with circuits specifically designed for Apple devices and one for Android. However, be aware that if we have an Apple device with iOS 5 or higher, you can use both ports with no problems.
The two USB ports for maximum 3A power divided between the two outputs.
I mainly use this battery to charge my iPhone 5 (it should, however, use the cable that came with the iPhone because the Lighting adapter is not included with the battery. I made four full recharges my iPhone 5 with Anker battery charge.
No problem either to charge my iPad 3, iPad Mini and my little top bluetooth speaker.
This will really be super convenient when my next trips to the mountains or anywhere else when I would have no power outlet is available.
In short, a really good quality product, easy to use and very powerful! A buy without hesitation.
