Glossy Muanfwangosi - Has anyone replied, or did you figure it out? If not, you must line up the prongs with the connectors on your battery. If your battery is in properly and the light is blue, then your battery is charged. On my charger the light was blue when I plugged in [before I inserted my battery into the charger]. After putting the battery in, the charger went to a red/ pink color. Which meant my battery was charging.
I wasnt sure how it would work when I first saw the advert on ebay, but you just slide the battery in until the battery connectors meet the prongs and battery slides into place. I am not sure about all batteries. My batteries are for my Samsung cell phone, so they fit perfectly into the charger. There was no need to figure where the prongs connect.
Not sure about the 30 minutes charge time quoted earlier though. I would think it would depend on the type of battery and also on the 'mAh' of the battery. And I'm not sure how long the 'regular' samsung batteries will take to charge. I purchased 2 super batteries [2750 mAh] with the charger. Both arrived at only 60%. So I put one in the charger. It has been on the charger now for 6+ hours and the light has still not turned blue. I took the battery out after about 5 hours to check to see if is was charging. It was at 87%.
Since I am new to this charger and to super mAh batteries, I am not sure if it should take this long, or if my charger is somehow defective. Anyway, hope this is helpful. Best of luck. ^ ^