Here's the owners manual they should have included with the Opteka BP-SC4000 Backup Battery and Charger that's sold on Amazon: http://www.amazon.com/Opteka-BP-SC4000-Powered-Capacity-4000mAh/dp/B005ZSVZRY
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When placed in direct sun light, the four LEDs at the bottom right of the device will flash from left to right. The rate at which they are flashing indicates the rate at which the internal battery is being charged. The faster they flash, the more power you are getting from the sun. Put the solar cells in direct sun light for maximum charge.
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When the device is fully charged (although it does not have to be fully charged to attempt to charge your device) all the LEDs will go out.
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While the battery is charging (and the LEDs are flashing) you can press the silver button quickly to see an indication of the internal power level of the battery. (1 LED = 1/4 charge, 2 = 1/2 charge, 3 = 3/4 charge, and *none) = fully charged)
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To charge your device, plug it into the included USB adapter. If the solar LEDs were still flashing, charging of your device will begin immediately. If the LEDs were not flashing, hold the silver button down for 3 seconds to begin charging your device. When charging is complete the LED will go out.
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You can pre-charge the battery in the Opteka BP-SC4000 by connecting a standard mini (not micro) USB cell phone charger into the connector on the side of the solar charger (the one marked "input"). (If you are going on a trip you might want to precharge the internal battery so you can charge your device before the sun comes up.)